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Glossary

Meiosis

The form of cell division by which egg and sperm cells are formed. Unlike normal cell division (mitosis), the number of chromosomes in the resulting cells is half that in the original cells.



Articles using this Glossary Item

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Sperm, eggs and embryos: how do we define them as science offers new possibilities?

18 December 2017 - by Dr Avi Lerner

The Progress Educational Trust (PET)'s Annual Conference 'Crossing Frontiers: Moving the Boundaries of Human Reproduction' discussed some of the most important ethical and scientific questions facing human reproduction. The first session, chaired by Sarah Norcross, the Director of PET, tackled the very fundamentals. What is a sperm? What is an egg? And what is an embryo?... [Read More]

Preimplantation genetic screening: unvalidated methods discard healthy embryos

11 December 2017 - by Norbert Gleicher

A seemingly brilliant hypothesis of preimplantation genetic screening arose in the 1990s when Dr Yuri Verlinsky proposed using polar body biopsies to detect chromosomal abnormalities in embryos prior to transfer in IVF... Healthy embryos are discarded by unvalidated PGS

Older parents pass down more genetic mutations

25 September 2017 - by Dr Rosie Gilchrist

Parents pass on more new genetic mutations to their children with age, and fathers pass on more than mothers, according to a study... [Read More]

Regeneration of oocytes from discarded genetic material: will this double IVF success rates?

28 November 2016 - by Dr Philip Lewis and Professor Daniel Brison

A major factor limiting the effectiveness of IVF is the availability of high-quality egg cells from a patient. But new research suggests that the use of polar bodies might create two oocytes for the price of one... [Read More]

Autism link to mutations in mitochondria

07 November 2016 - by Helen Robertson

Children with autism spectrum disorder have twice as many harmful mutations in their mitochondrial DNA as their siblings, a study has found... [Read More]

Gene involved in egg and sperm production linked to Down's syndrome

15 August 2016 - by Dr Katie Howe

Researchers have identified an enzyme that helps ensure egg and sperm cells contain the right number of chromosomes... [Read More]

Reassurance for mothers over mosaic aneuploidy in CVS

03 May 2016 - by Professor Magdalena Zernicka-Goetz

Although our recent findings on the fate of aneuploid cells in mosaic embryos have indeed been somewhat misrepresented in the press, our findings may still constitute a strand of hope for mothers who have had early test results showing mosaic aneuploidy... [Read More]

Spanish lab creates human sperm precursors from skin cells

03 May 2016 - by Ayala Ochert

Spanish scientists say they have created rudimentary sperm-like cells from skin and bone marrow cells taken from adult males... [Read More]

Lab-made sperm used to breed healthy mice

29 February 2016 - by Helen Robertson

Scientists in China have used stem cells to create rudimentary sperm that successfully fertilised mouse eggs to produce healthy offspring... [Read More]

Preventing transmission of mitochondrial DNA disease: new developments

19 November 2012 - by Professor Mary Herbert

The energy required for our cells to function properly is mainly produced by mitochondria. Mitochondria are tiny structures within our cells, which contain their own DNA. The mitochondrial DNA (mtDNA) encodes a small number of the many proteins required to produce energy efficiently. Mutations in mtDNA cause a broad spectrum of diseases and degenerative disorders, which can be fatal.... [Read More]

Event Review: GENIE Public Engagement Lectures

22 October 2012 - by Marco Narajos

Bread and beer are not usually things that one would associate with diseases like cancer, dementia or Huntington's disease. This view was proved wrong by geneticists who gathered at the University of Leicester on 9 October 2012 for a series of lectures aimed at the non-scientist. It seems yeast can be inspiration for genetics research too.... [Read More]

An eggsample of why it is hard to prove a negative

30 July 2012 - by Professor Robin Lovell-Badge

Earlier this year, a paper claimed to have found cells, called ovarian stem cells, in the adult ovaries of both mice and humans. These cells could apparently be grown in large numbers in the lab and could retain the ability to give rise to eggs. A new study finds no evidence for the existence of germline progenitors able to produce eggs in postnatal ovaries. Is a lack of evidence sufficient to win the argument?... [Read More]

Every sperm is special, genome sequencing shows

23 July 2012 - by Antony Blackburn-Starza

Results of the first study to sequence the genomes of individual sperm cells obtained from one person have revealed significant genetic differences between them, confirming the belief that each sperm is unique. It is hoped the technique could be applied in fertility treatments to identify genetic mutations that may occur in the recombination process... [Read More]

Hype, hope and heresy – or why it is bad to eggsaggerate

12 March 2012 - by Professor Robin Lovell-Badge

I am all for challenging dogma, but to do so requires robust evidence and carefully drawn conclusions. In the case of Professor Jonathan Tilly's much-trumpeted study on stem cells in ovaries that can give rise to eggs, I feel that both were missing... [Read More]

Beyond the treatment of infertility

13 February 2012 - by Professor Mary Herbert

The advent of PGD extended the scope of IVF beyond the treatment of infertility. PGD is predominantly used to prevent transmission of genetic defects arising from mutations in nuclear DNA. However, it can also be used to reduce the risk of transmitting mutations in mitochondrial DNA (mtDNA), which cause a range of debilitating and life-threatening diseases... [Read More]

Ovarian stimulation linked to egg abnormalities in older mothers

04 July 2011 - by Dr Lux Fatimathas

European researchers have linked ovarian stimulation in women aged over 35 to increased chromosomal abnormalities. Genetic screening shows that the production of oocytes is disrupted during fertility treatment involving ovarian stimulation... [Read More]

Sperm from female stem cells?

04 February 2008 - by Dr Charlotte Maden

British scientists have created early-stage, human sperm from female stem cells, according to a news report in New Scientist magazine. It is claimed that the research will pave the way for same sex couples to have children that are genetically their own. However, other scientists are sceptical... [Read More]

PGS: select or reject? - it's not just about improving pregnancy rates

20 November 2006 - by Professor Alan Handyside

Ten years since the first reports of preimplantation genetic diagnosis for abnormal chromosome number, or aneuploidy, (now commonly known as PGS - preimplantation genetic screening), we are experiencing a prejudicial mistrust of a clinical approach that is generally accepted to be scientifically and clinically sound. Opponents of PGS frequently criticise its... [Read More]

Explaining mammal egg errors

27 October 2003 - by BioNews

As many as a fifth of a woman's eggs are genetically scrambled - but it's not because they can't check their chromosomes, say a team of UK and French scientists. A new study published in the journal Reproduction shows that egg-producing cells in mammals have a mechanism for checking their chromosomes... [Read More]

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