ScienceDaily (July 9, 2007) — Chromosome disorders in sex cells cause infertility, miscarriage and irregular numbers of chromosomes (aneuploidy) in neonates. A new study from Karolinska Institutet published in Nature Genetics shows how chromosome disorders can arise when sex cells are formed.

Sex cells contain a control station for monitoring the mechanism that ensures that the correct numbers of chromosomes are distributed during cell division. Scientists have now shown that there is an alternative distribution mechanism in female sex cells that cause chromosome disorders. Aberrant chromosomes orientate themselves like normal chromosomes, and this ability to adopt double identities protects them from detection by the control centre.

"We believe that this new fundamental mechanism can help to explain why chromosome disorders are so common in female sex cells," says Professor Christer Höög, leader of the study.

The research might eventually lead to new medical treatments able to reduce the risk of foetal damage.

Over 0.3 per cent of children are born with some kind of chromosome disorder. Most develop Downs Syndrome, or obtain the wrong number of sex chromosomes and develop Turner's or Klinefelter's syndrome. Turner's syndrome only occurs in females and is caused when one of the two X chromosomes is missing. Girls with Turner's have arrested development and if no treatment is given do not enter puberty. Klinefelter's syndrome affects males, who receive an extra X chromosome. Symptoms include concentration difficulties, poor motor skills and infertility.

Article: "Bi-orientation of achiasmatic chromosomes in mammalian MI oocytes contributes to aneuploidy"

Anna Kouznetsova, Lisa Lister, Magnus Nordenskjöld, Mary Herbert, Christer Höög

Nature Genetics, 8 July 2007

Story Source:

Adapted from materials provided by Karolinska Institutet, via EurekAlert!, a service of AAAS.

Related Stories

Male Sex Chromosome Losing Genes By Rapid Evolution, Study Reveals (July 17, 2009) — Scientists long have suspected that the sex chromosome that only males carry, the Y chromosome, is deteriorating. But until now, no one has understood the evolutionary processes that control this ...  > read more

Creating Males With Female Sex Chromosomes: Brain Gene Flicks The Switch On Gender (Aug. 20, 2007) — Researchers have discovered a way of creating a male mouse without a Y chromosome by manipulating a single gene in the developing ...  > read more

What Tips The Balance? Understanding Why X Chromosome Inactivation Can Be Skewed (Dec. 26, 2007) — To ensure that women and men express equivalent levels of the genes found on X chromosomes, one of the two X chromosomes in the cells of a women is inactive. X chromosome inactivation (XCI) occurs ...  > read more

Small RNAs Can Play Critical Roles In Male Infertility, Contraception (Apr. 10, 2009) — Scientists have discovered insight into the reproductive workings of the male sex chromosome that may have significant implications for male infertility and ...  > read more

Search ScienceDaily

Diagnosing Heartburn