In the week that the University of Leicester celebrates the 25th anniversary of the discovery of DNA fingerprinting (Thursday September 10) new findings from the world-renowned University of Leicester Department of Genetics reveal for the first time that the male and female do truly communicate –at least at the fundamental genetic level.
The research counters scientific theory that the X and Y chromosomes - that define the sexes - did not communicate at all.
The research is funded by the Wellcome Trust, and published in the American Journal of Human Genetics. In it Dr Zoë Rosser and colleagues have shown that exchange of DNA does actually occur between the X and Y in the regions previously thought to be completely isolated.
Professor Mark Jobling, who led the study, said: "Recently it was shown that the Y chromosome can talk to itself – swapping bits of DNA from one region to another, and potentially giving it a way to fix mutations that might affect male fertility. In this new research we've now shown that it actually maintains a genetic conversation with the X chromosome, potentially giving it a way to fix other kinds of mutations, too. So, maybe it's not quite the dysfunctional loner we have always imagined it to be."
The X and Y chromosomes have a vital role- sex is determined by them. Apart from the 22 pairs of regular chromosomes all of us share, women have two X chromosomes, while men have only one X but also the smaller Y chromosome. It's the Y that determines maleness by triggering development of testes rather than ovaries in the early embryo.
Professor Jobling said: "These days the X and Y are a very odd couple, but long ago, before mammals evolved, they were an ordinary pair of identical chromosomes, exchanging DNA in a companionable way through the process of genetic recombination. However, once the Y chromosome took on the job of determining maleness, they stopped talking to each other. The X remained much the same, but the Y set out on a path of degeneration that saw it lose many of its genes and shrink to about one third the size of the X. Some scientists have predicted that it will eventually vanish altogether.
"These new findings from the Department of Genetics of the University of Leicester now challenge this interpretation of the Y chromosome's fate."
The Leicester researchers discovered that the conversation between the X and Y chromosome goes both ways, and it's also clear that mutations arising on a decaying Y chromosome can be passed to the X – the Y chromosome's revenge, perhaps! Future work will assess how widespread X-Y exchanges have been during evolution, and what the likely functional effects might be.
Note to editors:
Contact:
Prof. Mark A. Jobling
Department of Genetics
University of Leicester
University Road
Leicester LE1 7RH, UK
Email: maj4@leicester.ac.uk
Tel.: +44 116 252 3427
This release refers to the article: "Gene conversion between the X chromosome and the male-specific region of the Y chromosome at a translocation hotspot" by Zoë H Rosser, Patricia Balaresque and Mark A Jobling, which has been published by AJHG - The American Journal of Human Genetics (vol. 85, pp.130-134)
The Wellcome Trust is the largest charity in the UK. It funds innovative biomedical research, in the UK and internationally, spending over £600 million each year to support the brightest scientists with the best ideas. The Wellcome Trust supports public debate about biomedical research and its impact on health and wellbeing. http://www.wellcome.ac.uk
University of Leicester - Times Higher Education University of the Year 2008/09
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ABOUT THE UNIVERSITY OF LEICESTER
- A member of the 1994 Group of universities that share a commitment to research excellence, high quality teaching and an outstanding student experience.
- Named University of the Year by Times Higher (2008) Shortlisted (2006, 2005) and by the Sunday Times (2007)
- Ranked top with Cambridge for student satisfaction amongst full time students taught at mainstream universities in England
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Founded in 1921, the University of Leicester has more than 20,000 students from 136 countries. Teaching in 18 subject areas has been graded Excellent by the Quality Assurance Agency- including 14 successive scores - a consistent run of success matched by just one other UK University. Leicester is world renowned for the invention of DNA Fingerprinting by Professor Sir Alec Jeffreys and houses Europe's biggest academic Space Research Centre. The latest Research Assessment Exercise adjudged Leicester to have world leading research in every subject panel and identified Museum Studies (at 65%) as having the highest proportion of world leading researchers compared with any other subject area at any university in the UK. Leicester also emerged as having one of the highest proportions of staff who are research active in the UK, with approximately 93% of staff submitted for the exercise. The University's research grant income places it among the top 20 UK research universities. The University employs over 3,000 people, has an annual turnover of over £200m, covers an estate of 94 hectares and is engaged in a £300m investment programme- among the biggest of any UK university.
Journal
American Journal of Human Genetics