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King's College London - Health: More than a medical matter

Issue 485 (24 November 2008)

 

Welcome to BioNews by email, published by the Progress Educational Trust, providing you with news, comment and reviews on genetics, assisted conception, embryo/stem cell research and related areas.

Visit the BioNews website at www.bionews.org.uk where you can subscribe for free to receive BioNews by email in one of three formats, and search the archive of more than 6,000 articles.

 

 

CONTENTS

Comment

News Digest

Reviews


 



A Buddhist perspective on pre-implantation genetic diagnosis

24 November 2008

By Peter Harvey

Professor of Buddhist Studies, University of Sunderland

Appeared in BioNews 485
Buddhism is a non-theistic religion which does not see the world or human life as created by a deity. It does, however, have a strong emphasis on ethics and non-violence, on the intention not to harm and compassion.

Buddhism sees a human life as coming after past rebirths in which the individual may have been a human, a heavenly being, an animal, a ghost or a being suffering in a hell. Future rebirths may be of any of such types, depending on the moral quality of a person's actions, their karma. For example, physical cruelty is seen as likely to lead towards a hellish rebirth and generosity and kindness to a human or heavenly one. The working of karma is not about 'rewards' and 'punishments' but a natural process in which a volitional act is like a seed and its karmic results are like fruits. A Buddhist's long-term aim is to overcome the repeated round of countless rebirths, by attaining Nirvana, and to help others do so. Other aims are to bring more happiness to all in this life, and at least gain a good rebirth, as a human or in a heaven.

Rebirth as a human is seen as a relatively rare and precious opportunity for moral and spiritual development - a 'precious human rebirth' - and so to kill a human is definitely worse than killing an animal, although the deliberate killing of any being is against Buddhist ethics. Human life is seen as starting at conception, when the stream of consciousness from a previously deceased being enlivens an egg in the process of being fertilized (whether in a womb or in an IVF test-tube). The question of when the developing embryo 'becomes a person' is not really an issue for Buddhists. An embryo at any stage is alive, conscious and human, though of course its physical and mental faculties take time to fully develop. Consequently, Buddhism sees abortion as morally problematic; a monk who aids an abortion is expelled from the monastic order just as if he had been involved in the murder of a child or adult. Buddhists vary, though, in the extent to which they feel the Buddhist moral view on abortion should be encoded in law. For example, some American Buddhists have argued for an 'anti-abortion/pro-choice' view (1).  While, in principle, the age of the embryo does not affect its moral status, in practice one can argue that as the embryo develops, and a relationship with it builds up in the minds of the parents, it becomes more morally perverse to end its life.

How might this perspective inform a Buddhist view of PGD (preimplantation genetic diagnosis)? Here, the basic motivation behind the act is, firstly, to benefit the parents by enabling them to have a child, but not burdening them with an impaired one, and, secondly, not to bring into the world a child suffering from a severe illness. While some may see moral problems with regard to the first goal, due, for example, to concern over an implied slight to those who are disabled, Buddhism sees the main moral issue in relation to the second. Once one has a living embryo one has a very early human being with the genes that it has. Clearly, if one has a group of embryos and one is only going to implant one, or perhaps two, it is better to implant those one knows to be genetically healthier, if one has this knowledge.

Yet this also involves deliberately ending the lives of the remaining embryos - as can also happen in IVF without pre-implantation genetic diagnosis. Given the value of human life, one should only do this in cases of specific, severe genetic illness. It may be that a person born with Down's syndrome goes on to live a life of greater generosity and kindness than someone without the condition and thus makes better spiritual use of their human life. If the embryos are not implanted it should not be done lightly but in acknowledgement that one is ending early human lives with a certain level of consciousness, if not yet consciousness of their environment. Perhaps a simple, voluntary ceremony could mark the event to help the parents deal with their feelings in a clear, conscious and respectful way. Buddhists might also do good deeds on behalf of the deceased embryo(s) so that it might have a chance to mentally participate in the act and benefit karmically.

For Buddhism, it is not simply a question of whether or not to 'create' a being that may have a problematic future. While Buddhism denies that everything that happens is due to karma, who one's new parents are can only be due to karma and it remains highly likely that the specific gene-set one gets from them, including any genetic impairment, is due to karma too. It may be that which sperm and egg successfully fuse to produce a viable embryo is subject to karmic influence: what one might call karmic genetic screening.

However, a severely disabled child, who will suffer extremely poor quality of life or die very young, will need constant care and may place great strain on the parents. In some cases this strain may be intolerable and psychologically and spiritually damaging. It is only, I think, at this point that the morally negative aspects of PGD may be outweighed by the potential spiritual damage that may result from not doing it. One cannot simplistically say that it must be a parent's karma to suffer through having a severely disabled child so they had better just put up with it. They have a choice and that choice needs to be exercised with the utmost care and compassion all round, considering both their own interests and that of any being they will be inviting into their lives.

Alternatives to PGD, which avoid a route involving dead embryos are:

a) to remain childless,

b) to adopt a child,

c) to have a child using a donated sperm via intrauterine insemination (IUI) [where appropriate], or

d) to have a child without knowing whether it will be damaged or not.

Some argue that it is best for a Buddhist not to take the risk, but to accept childlessness or go for adoption. Either way, no-one's short life is deliberately ended and, with adoption, someone is positively helped.

 

 

 

RELATED ARTICLES FROM THE BIONEWS ARCHIVE

15 December 2008 - by Angeliki Kerasidou 
The Progress Educational Trust's conference in London titled 'Is the Human Embryo Sacrosanct? Multi-faith perspectives' on the 19th of November 2008 was an excellent event. It brought thinkers from most major religions and an atheist together, and asked them to address the question 'Is the human embryos sacrosanct?' The purpose... [Read More]

16 November 2008 - by Professor David Jones 
I think the title of Progress Educational Trust's forthcoming conference ('Is the embryo sacrosanct? Multi-faith perspectives.' - see Recommends for details) has been very well chosen. It connects with other kinds of questions - legal, scientific, theological - but in itself it is a specifically moral or ethical question. 'Is the human embryo... [Read More]
10 November 2008 - by Dr Farouk Mahmoud 
The desperation of the infertile, the scientific zeal of the physician and scriptural restrictions posed by Shari'ah appear to have different pathways.' Muslims constitute over a fifth of the global population, ninety per cent being Sunnis and the rest Shi'a. Of the 50-80 million infertile world-wide, more than half... [Read More]
09 November 2008 - by Rabbi Dr Jonathan Romain 
The title of this article is deliberately modest in its claims - 'a Jewish view' - for there is no such thing as 'the Jewish view'. As with Christianity or Islam, there are a wide range of different traditions, ranging from the ultra-conservative to the most liberal, and it is possible to... [Read More]
03 November 2008 - by Alison Cranage 
An international poll has shown a range of opinions about when human life begins biologically. It comes ahead of a proposed constitutional amendment in Colorado, US, which could confer legal rights to embryos at the point of fertilisation. The poll was commissioned by Reproductive Biology Associates, an... [Read More]
27 October 2008 - by Dr Farrokh B Sekaleshfar 
1) The embryo Sunnism and Shi'ism comprise approximately eighty and twenty per cent of the Islamic world, respectively. Like other monotheistic religions, Islam regards one's personal identity, or one's 'I' in terms of personhood, as being tantamount to one's immortal, immaterial and rational soul. Differences between the religions, however, exist... [Read More]



'Think of a number, then double it': playing a numbers game with donor conception?

24 November 2008

By Professor Eric Blyth and Dr Marilyn Crawshaw

co-chairs of the Project Group on Assisted Reproduction (PROGAR) and, respectively, Senior Lecturer in Social Work at the University of York and Professor of Social Work at the University of Huddersfield and Visiting Professor of Social Work at Hong Kong Polytechnic University.

Appeared in BioNews 485
The report of the British Fertility Society's (BFS) Working Party on Sperm Donation Services in the UK (1) recently hit the headlines, following an associated editorial in the British Medical Journal (2). However, the report's proposals for a fundamental overhaul of the current arrangements for organising donor recruitment were considered less 'newsworthy' than suggestions that the maximum number of families containing a child conceived from the gametes of a single donor should be increased (3).

Currently, the Human Fertilisation and Embryology Authority (HFEA) limits the use of gametes from a single donor to a maximum of 10 families, although it notes that this is an arbitrary figure (4). A majority of the BFS Working Party supported raising this to 20 families, while a minority advocated an increase to 15 and some suggested no change (we understand that those outside the majority group included representatives of counsellors and donor-conceived families, though this significant fact was not reported).  In the absence of any consensus, either domestically or internationally, on the principles underlying donor limits (5) the suggestion of raising them warrants further discussion.

Current donor limits in the UK, as in many other jurisdictions, were established within the context of donor anonymity. The risk of 'unwitting incest' between genetic relatives was considered of greater concern than the challenges faced by the donor-conceived in '[coming] to grips with multiple genetically-linked siblings in a number of different families' (6). Among jurisdictions that enable the donor-conceived to learn the identity of their donor Sweden sets the donor limit at six children, Switzerland eight, New Zealand ten and the Netherlands 25. Where the criterion is the number of families Austria restricts donations to three marriages (or couples in a de-facto marriage) and Finland to five recipients. Proposed legislation in New South Wales, Australia also imposes a five-recipient limit that includes the marital relationships (but not the non-marital liaisons) of the donor which resulted in the birth of a child. The limit in Western Australia is five families. Like the UK, Victoria has a limit of ten families, although proposed legislation would include in this number families with children by the donor's current or former partner. Norway combines both criteria, with limits of six or seven families and 12-14 children.

The context within which most proposals to increase donor limits arise is that of 'supply and demand'; where the two do not balance, either input or output requires attention. We approach the issue from an alternative perspective which focuses on the well-being of the families built as a result of donor conception and, in particular, the individuals whose entire lives are affected as a consequence of being donor-conceived. From this perspective, questions of supply and demand are the wrong questions to ask.Indeed, we need to remember that we are still at the stage of asking questions rather than providing answers. Both the BFS (1) and the HFEA (4) acknowledge the paucity of good-quality social science research relevant to this field. Anecdotally, we hear that (at least some) donors in the UK already place lower limits on the maximum number of families that may include their genetic offspring. However, this information is not routinely collected, much less analysed in an attempt to understand donors' perspectives on the children they are a party to conceiving and the families they help to build. Similarly, little is known about the views of those who have the most at stake, donor-conceived people themselves. We are aware of a single research study that has highlighted the concerns of the donor-conceived about having potentially large numbers of genetic relatives. According to the report, some participants were 'deeply disturbed by the thought of almost a tribe of offspring from their provider' (7). Considering the risk of consanguinity solely in terms of probability - and then rejecting it, like the BFS (1) and the HFEA (4), as extremely unlikely - fails to consider the impact of the fears of donors (in relation to their own children), the donor-conceived and their parents of discovering that a former or existing sexual partner was in fact a half-sibling or biological parent (8, 9).

Until we have relevant, good-quality empirical evidence that can inform the direction of future policies, donor limits should be left alone.

  

 

RELATED ARTICLES FROM THE BIONEWS ARCHIVE

26 September 2011 - by Jessica Ware 
The Human Fertility and Embryology Authority (HFEA), the UK's fertility regulator, has admitted breaches of the sperm donation limit have occurred, following news that one donor has fathered 17 families... [Read More]
11 January 2010 - by Antony Blackburn-Starza 
A British woman has travelled to Denmark to undergo donor insemination after the fertility clinic where she had been receiving treatment in the UK ran out of sperm, BBC News reports. Single and 41, Abby, who is using a pseudonym, made the decision after three unsuccessful insemination attempts in the UK using donated sperm. Once the clinic informed her there was no more sperm available she contacted the Danish clinic. Following treatment there she gave birth to a... [Read More]
12 December 2008 - by Helen Clarke 
The BFS recently published its report on sperm donation services in the UK (1), in which various suggestions were put forward for overcoming the current shortfall of sperm donors. These included increasing the number of families to be treated per donor and changing thresholds for acceptance of donors. The BFS... [Read More]

17 November 2008 - by MacKenna Roberts 
Sperm donation services require infrastructural reorganisation, 'sperm-sharing' incentive schemes and regulatory reforms to overcome the severe shortage presently causing 'anguish' to thousands of infertile couples in the UK each year and to the health professionals unable to provide treatment to their patients, according to fertility experts writing... [Read More]



Family history predicts high breast cancer risk despite negative gene tests

23 November 2008

By Sarah Guy

Appeared in BioNews 485

A study undertaken in Canada shows that women who test negatively for gene mutations associated with breast cancer may still be at high risk if there is a strong presence of the disease in their family. Author of the study Dr Steven Narod, Canada Research Chair in breast cancer at the University of Toronto said, 'it was assumed that most of the risk could be explained by [gene] mutations', referring to the mutations in the genes BRCA1 and BCRA2 which are linked to particularly aggressive hereditary breast cancer. However, Dr Narod's study indicates that BCRA gene mutations are only responsible for breast cancer in one in every five families tested.

Narod's study followed 1,492 Canadian women who did not carry the mutated genes but had a history of breast cancer in the family. After five years, these women were four times more likely to have developed breast cancer than the average woman.

'The findings suggest that additional genes, hormones, or other unknown factors, perhaps environmental, are also responsible for causing breast cancer', Narod said. 'It is clear to me that the risk is high enough that we need to discuss options such as breast MRI (Magnetic Resonance Imaging) screening and chemoprevention with tamoxifen or raloxifene. Our hope is to be able to prevent or pick up on breast cancer early enough to stop patients from dying'.

It is thought this revelation will enable clinicians to give better counselling to families with a prevailing history of breast cancer but who do not necessarily present with the associated gene mutation. Kelly Metcalfe, also of the University of Toronto said 'it has been difficult to counsel women without a mutation...For a woman with a significant family history of breast cancer, without a BRCA1-2 mutation, we can now say that she has an approximate 40 per cent risk of developing breast cancer'.

Dr Narod recommended that women without gene mutations but with three or more family members with breast cancer should undergo MRI screenings and consider taking tamoxifen, an oestrogen suppressant used to prevent breast cancer tumours. 'You can reduce the risk from 40 to 20 per cent - pretty dramatic figures'.

Beth Peshkin, a genetic counsellor at Georgetown University, Washington said that the findings were crucial for women considering having genetic testing. 'This is contrary to what I think the common perception is;' Peshkin said, 'a negative test doesn't provide reassurance'.

Some positive news came from the study to show that although carriers of the BCRA genes are also at increased risk of ovarian cancer, the women in Dr Narod's study were not.

 

SOURCES & REFERENCES
CBC News | 18 November 2008
 
Associated Press | 17 November 2008
 
WebMD | 17 November 2008
 



Assisted reproduction associated with elevated risk of birth defects

23 November 2008

By Lorna Stewart

Appeared in BioNews 485

A study published last week in the journal Human Reproduction found an elevated risk of birth defects amongst babies conceived through assisted reproductive techniques, including IVF. The research, headed by Dr Jennita Reefhuis of the US Centre for Disease Control and Prevention, used data from the National Birth Defects Prevention Study to compare the health of babies born to women who had used the techniques with infants born to women who had conceived naturally.

Dr Reefhuis and colleagues found that babies conceived using assisted reproductive techniques are between two and four times more likely to have certain birth defects than those who were conceived naturally. They are twice as likely to be born with a cleft lip, four times as likely to have abnormalities of the oesophagus or rectum, and two to three times as likely to have cardiac defects. The researchers point out, however, that even with the increased risks birth defects are still uncommon in these babies.

All the births included in the study were single births, though multiple births are relatively common in assisted reproductive techniques. Multiple births in general are known to be at higher risk of birth defects, and this is one of the reasons that techniques such as IVF have previously been thought to be associated with a higher incidence of birth defects. This study also corrected for other factors such as the age of the mother, folic acid use and alcohol intake.

The researchers are explicit in their report that they do not know the cause of the elevated risks. 'Our findings could have been because of underlying infertility, small (sample) numbers or chance,' they said. Dr James Grifo, director of the fertility clinic at New York University Medical Center, US, agrees. He feels that due to the small sample size (281 assisted reproduction babies, 14,095 babies conceived naturally) more research is needed to confirm the findings. He also said that if the association with birth defects was real, the underlying cause was more likely related to the patients' infertility than to the treatments they had undergone.

'Any couple who is considering these treatments wants to be aware of all the pros and cons of the treatment,' Dr Reefhuis said, adding 'I think it's important for couples to be aware that there may be some increased risk for birth defects as well.' Professor Michael Chapman, a senior fertility specialist with IVF Australia, said 'There's no question that the evidence shows a slight increase, and responsible IVF doctors are saying that to their patients. But if your only way forward is IVF, then an increase in risk from one in 100 to two in 100 for most people is an acceptable risk.'

 

SOURCES & REFERENCES
LA Times | 18 November 2008
 
Reuters | 17 November 2008
 
The New York Times | 17 November 2008
 
The Age | 19 November 2008
 

RELATED ARTICLES FROM THE BIONEWS ARCHIVE

19 November 2012 - by Nicola Davis 
Infants conceived by IVF are at significantly greater risk of birth defects compared to naturally conceived babies, announced scientists at a conference last month... [Read More]
26 May 2009 - by Ben Jones 
Two studies have provided an insight into the health implications of using assisted reproductive technologies (ARTs). The first finds that twins conceived by ART are more likely to be born preterm, be of low birthweight and to be 60 per cent more likely to be admitted into... [Read More]
23 March 2009 - by Ailsa Stevens 
The UK's Human Fertilisation and Embryology Authority (HFEA), the government's fertility watchdog, is updating its guidelines to recommend that doctors make couples aware of the potential risks to children conceived by IVF. The decision follows the publication of a study by the Centers for Disease Control and... [Read More]
23 February 2009 - by Sarah Guy 
A large study has investigated the potential genetic risks to children conceived by in vitro fertilisation (IVF). It confirms earlier research indicating that babies born following assisted conception have a small increased risk of certain genetic health problems. The New York Times reports that in November last... [Read More]



World's first tissue-engineered whole organ transplant is a success

23 November 2008

By Adam Fletcher

Appeared in BioNews 485

A Colombian woman has become the world's first recipient of a windpipe grown in part from her own cells. Published in the Lancet journal last week, the team of surgeons from Spain, the UK and Italy, orchestrated the world's first tissue-engineered whole organ transplant. Professor Paolo Macchiarini, of the Hospital Clinic of Barcelona, carried out the operation in June this year. The success has led some to herald the technique as the beginning of 'a new age in surgical care'.

Mother-of-two Claudio Castillo, 30, was left barely able to breathe after a tuberculosis infection left a bronchus irreversibly damaged. Surgeons rarely recommend a trachea transplant, as it condemns a patient to a life dependent on immunosuppressive drugs, leaving them open to other infections. The most common resort for people in similar positions is to remove a lung, which improves health but invariably shortens lifespan. However, given the option of undertaking an experimental 'tissue engineering' surgery, so far only tried on pigs, Ms Castillo consented.

To start, the Spanish team removed seven centimetres of trachea from a deceased organ donor. Maria Teresa Conconi and colleagues at the University of Padua then stripped the windpipe of all trace of the donor's cells, using a potent mixture of detergent and enzymes. After six weeks, just a collagen 'scaffold' remained. In the meantime, bone marrow stem cells from Ms Castillo's hip had been sent to Bristol, where they were induced into becoming cartilage cells. Upon their return to Barcelona - a return voyage nearly ruined by one airline company's bureaucracy - the collagen scaffold was suffused with the cells in a special bioreactor developed at the Polytechnic of Milan. Another Bristol group seeded epithelial cells, taken from Ms Castillo's airways, inside the donor trachea. After four days of repopulating the scaffold with cells, the new trachea was sculpted to shape and inserted in place of the damaged bronchus.

Professor Martin Birchall, professor of surgery at Bristol, who helped differentiate the stem cells, was delighted with the success. 'Surgeons can now start to see and understand the very real potential for adult stem cells and tissue engineering to radically improve their ability to treat patients with serious diseases', he said.

The major benefit of the necessarily laborious procedure is clear - after five months, there is still no sign of transplant rejection, since Ms Castillo's immune system has no difficulty in recognising her own cells. The hope is that the operation might become a reality for other transplant operations.

 

SOURCES & REFERENCES
The Daily Telegraph | 20 November 2008
 
The Guardian | 19 November 2008
 
BBC News Online | 19 November 2008
 
New Scientist | 19 November 2008
 

RELATED ARTICLES FROM THE BIONEWS ARCHIVE

04 February 2013 - by Dr Charlotte Warren-Gash 
The bacteria that cause tuberculosis (TB) evade immune cells and drug treatments by hiding in bone marrow stem cells, according to research... [Read More]
30 July 2012 - by Daryl Ramai 
The Irish boy who had pioneering surgery two years ago to implant a new windpipe partially derived from his own stem cells is healthy and back at school. A follow-up study published in The Lancet medical journal reports that Ciaran Finn-Lynch, now 13, is breathing normally and no longer needs anti-rejection medication... [Read More]
21 November 2011 - by Dr Zara Mahmoud 
The world's first stem cell therapy to repair torn cartilage in the knee has been brought one step closer. Professor Anthony Hollander, co-founder of University of Bristol spin-out Azellon Cell Therapeutics, has just received funding of £65,000 to carry out clinical trials on the use of a patient's own stem cells for knee repair... [Read More]
11 July 2011 - by Dr Rebecca Robey 
Surgeons have successfully transplanted a synthetic organ into a human for the first time. In a groundbreaking operation, a cancer patient's windpipe was replaced with an artificial replica that had been grown using his own stem cells.... [Read More]
16 August 2010 - by Marianne Neary 
An 11-year-old boy has returned home after becoming the first child to undergo a pioneering surgery which used his own stem cells to rebuild his windpipe. The operation, which took place in March this year at Great Ormond Street Hospital in London, has been hailed as 'a success'... [Read More]



New technology discovered for detecting cancer in the blood stream

24 November 2008

By Ben Jones

Appeared in BioNews 485

In a study published last week it was revealed that tumours release small sacs of genetic material that can be used to identify a tumour's exact type and which mutations it possesses. The study, produced by scientists at Massachusetts General Hospital in Boston and published in the journal Nature Cell Biology, may lead to a reduced reliance on technically difficult and risky biopsies, utilising a simple blood test to identify tumours.

The discovery goes beyond merely identifying the type of cancer, however, as the sacs of material (known as exosomes) are not just a by-product of the tumour but are also involved in the active proliferation of the tumour. The exosomes transmit instructions to other cells that control the way those cells behave. For example, the exosomes might stimulate additional blood vessel growth, so as to provide the cancer with more nutrients and thus making its growth more aggressive. It was not previously known that cancer had such a communication mechanism, and this discovery may lead to explanations for differential growth rates between different forms of tumour.

Existing blood test techniques for detecting cancers are based on interpreting levels of other chemicals within the blood (such as the prostate specific antigen "PSA" test for prostate cancer). The blood test was also found to be even more effective than analysis of surgically sourced biopsy material. In the study it detected specific mutations in two patients out of twenty-five that had been missed using traditional biopsies. Additionally, it allows clinicians to test for cancer before the tumour is even of a size detectable by X-ray or MRI (magnetic resonance imaging).

In an interview with Reuters, Xandra Breakefield of Massachusetts General Hospital in Boston said that the results were important as "We didn't realise [tumours] had this external means of communicating with their surroundings". Lab-mate Johan Skog noted "It's a form of cell communication that normal cells use but tumour cells use with a vengeance".

In the short term this technology, already licensed to Exosome Diagnostics Inc., has the possibility of detecting and specifying tumours earlier, with greater accuracy and in a less invasive manner. However, in the long term, with greater understanding of the mechanisms at work, it may be possible to use this discovery to create alternative exosomes that will interrupt this messaging system and potentially slow tumour growth.

 

SOURCES & REFERENCES
Reuters | 16 November 2008
 
The Washington Post | 17 November 2008
 
ScienceDaily | 17 November 2008
 



African and Asian genomes sequenced

24 November 2008

By Ailsa Stevens

Appeared in BioNews 485

Scientists have for the first time sequenced the complete diploid genomes of an Asian and an African. It is hoped that the research, published in the journal Nature, will help to shed light on how people from different ethnic backgrounds respond to medicine and help to explain the unusually high or low incidences of certain diseases seen among some populations.

The two anonymous individuals, one of Nigerian and the other of Han Chinese descent, are the first non-Europeans to have had their genomes sequenced. Jim Watson, who discovered the structure of DNA with colleague Francis Crick in 1953, and Craig Venter, one of the scientists to sequence the Human Genome, - both Europeans - are the only other two individuals to have published their complete genome sequences.

The African genome sequence is the work of an international consortium, including researchers at the Wellcome Trust Sanger Institute near Cambridge. The Asian genome was the work of the Beijing Genomics Institute in China, who announced the completed sequence in 2007, but have only now published it.

When the first human genome sequence was completed in 2003, it took years and cost millions of pounds. However, for these studies the researchers used next generation sequencing machines by the company Illumina Inc., based in California, to sequence the two 3 billion base-pair DNA sequences in just months and at a fraction of the cost.

While sequencing entire genomes is now relatively straightforward, making sense of the information they contain remains a significant challenge. The main goal of genome sequencing projects is to identify SNPs  (single nucleotide polymorphisms) - single 'letter' changes in the DNA sequence - which might be associated with disease susceptibility or drug response.

The African genome team reported around 4 million SNPs and the Asian genome team 3 million, with many of these common to those identified previously in Watson and Venter's genomes. However, further studies will be necessary to determine the effect of most of genetic variants on a person's health - if any.

 

SOURCES & REFERENCES
scienceblogs.com | 05 November 2008
 
PHG Foundation | 16 November 2008
 
The Associated Press | 05 November 2008
 

RELATED ARTICLES FROM THE BIONEWS ARCHIVE

09 May 2011 - by Mehmet Fidanboylu 
A genetic predisposition towards autoimmune disease may be associated with lower pregnancy rates in IVF, a US study suggests. The findings offer a possible explanation for differences in IVF treatment outcomes between different ethnic groups.... [Read More]
12 July 2010 - by Dr Charlotte Maden 
Stepping into the contentious world of race, ethnicity and genetics, a paper published in this week's Nature claims to have shed new light on the geographical origin of the many 'Jewish Diaspora' communities from around the world... [Read More]
28 June 2010 - by Ben Jones 
The Wellcome Trust has joined forces with the US National Institute of Health (NIH) to coordinate a major new genetics study in Africa.... [Read More]
22 February 2010 - by Dr Rachael Panizzo 
Comparing the genomes of Archbishop Desmond Tutu and !Gubi, a Khoisan elder from the Kalahari, reveals that, although they are geographical neighbours, their genomes are as different from each other as they are from European or Asian individuals. These findings, published in the journal Nature, reflect the extent of human genetic diversity on the African continent.... [Read More]

10 November 2008 - by Alison Cranage 
In a world first, scientists at Washington University, US, have sequenced the entire genome of a woman with acute myelogenous leukaemia (AML). They sequenced DNA from both normal skin cells and malignant tumour cells and found that 10 genes were mutated in the cancerous cells. The findings... [Read More]
03 November 2008 - by Lorna Stewart 
The Personal Genome Project (PGP) has released its first set of results. The study, based at Harvard Medical School and headed by Professor George Church, aims to sequence the genomes of 100,000 volunteers and make the majority of the information availably publically. At a press conference held... [Read More]
21 April 2008 - by Dr Jess Buxton 
James Watson, one of the scientists who reported the double helix structure of DNA in 1953, has now had his own genetic make-up completely decoded. A paper published in the journal Nature last week describes the sequencing of Watson's genome to reveal the precise order of... [Read More]
27 January 2008 - by Dr Jess Buxton 
An international project to read the entire genetic code of at least 1000 individuals will result in a comprehensive catalogue of human variation that will accelerate efforts to identify genetic factors involved in health and disease, scientists announced last week. The '1000 Genomes Project' will take... [Read More]
10 September 2007 - by Dr Jess Buxton 
The scientist who lead the private effort to sequence the human genome has revealed his own complete genetic make-up. The unveiling of J. Craig Venter's genome in the open access journal PloS Biology marks the first time that the complete DNA sequence of an individual has... [Read More]



Correction: Slow-frozen embryos seem to produce healthier babies in IVF

24 November 2008

By BioNews

Appeared in BioNews 485

In BioNews 484, we published a story reporting on new evidence to suggest that in IVF 'vitrified' embryos may be better than 'fresh' embryos. It has been brought to our attention that the technique used to store embryos in these studies was in fact 'slow-freezing', or 'controlled-rate freezing', and not vitrification as reported.

Controlled-rate freezing avoids the formation of potentially damaging ice crystals by allowing time for the concentration of solutes in the embryo to reach equilibrium in a cryoprotectant (a form of anti-freeze), before cooling in a predetermined, controlled way. Vitrification also aims to avoid the formation of ice crystals in the embryo, but does so by boosting the levels of cryoprotectant in order to avoid freezing and produce a glassy or 'vitreous' state at very low temperature.

While controlled rate freezing has been used in embryo storage since the 1980's, resulting in hundreds of thousands of healthy births, vitrification is, by comparison, a relatively new technology, which has so far only been attempted in a relatively small number of births. It would therefore have been impossible to achieve the large sample sizes recorded in these studies if not using the significantly more established slow-freezing technique.

 

SOURCES & REFERENCES

RELATED ARTICLES FROM THE BIONEWS ARCHIVE

17 November 2008 - by Alison Cranage 
Three new independent studies have provided further evidence that embryos stored using slow-freezing techniques may be better than fresh for IVF. The studies were presented at the American Society for Reproductive Medicine conference in San Francisco, US, last week. The studies indicate that using frozen embryos rather... [Read More]



Genetic tests no better than medical check ups for predicting diabetes

24 November 2008

By Dr Rebecca Robey

Appeared in BioNews 485

Genetic tests are no better at predicting an individual's risk of developing type-2 diabetes than conventional assessments based on family history and physical factors such as blood pressure and weight, according to a new study by US scientists.

The research team, led by Dr. James Meigs of the General Medical Division at Massachusetts General Hospital in Boston, analyzed medical data from over 2,300 volunteers that had been followed over a 28-year period as part of a study into cardiovascular disease. Of these individuals, 255 developed type-2 diabetes during the study period. The researchers looked for the presence of 18 different gene variants associated with type-2 diabetes and scored each individual's likelihood of developing the disease based on the particular combination of genes they carry. They then compared this to a risk assessment based on the detailed medical records of each participant, which documented family history of diabetes, weight, cholesterol, blood pressure and blood sugar levels. They found that although their gene-scoring system was a good measure of the risk of diabetes, it was no more accurate or useful than traditional methods of physical examination.

These findings were supported by a second study carried out in Sweden and Finland, led by Dr. Valeriya Lyssenko of Lund University, Sweden, which followed nearly 19,000 participants, 2,201 of whom developed diabetes, over an average of 23 years. They compared the presence of 16 gene variants linked with diabetes with physical risk factors and reached a similar conclusion to the American researchers.

Type-2 diabetes is a major health burden worldwide, and affects around two million people in the UK. There are around 25 gene variants that are linked with an increased likelihood of developing the disease. A simple genetic test to identify those most at risk is an attractive prospect. However, the outcome of these two studies indicates that we do not yet have the understanding to implement such a test. Dr Meigs commented: 'With our current knowledge, the measurements your [doctor] makes in a standard check up tell you what you need to know about your type-2 diabetes risk, and genetics doesn't tell you much more'. Nonetheless, he remains hopeful for the future, adding: 'as additional risk genes are discovered, the value of genetic screening is likely to improve'.

 

SOURCES & REFERENCES
Los Angeles Times | 19 November 2008
 
WebMD | 19 November 2008
 
Genetic screening may only modestly improve detection of diabetes
Medscape | 19 November 2008
 
Medical News Today | 20 November 2008
 
New England Journal of Medicine | 20 November 2008
 

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