• homologous
  • Second, the neo-sex chromosome is homologous to the sex chromosomes of mammals, which makes it possible - for the first time - to study mammalian X gene homologs in a novel, avian Z-linked environment where females are the heterogametic sex (ZW), and thus to draw direct parallels over the avian ZW-mammalian XY boundary. (lu.se)
  • chromosomal
  • Most likely this suppression was the result of a series of chromosomal inversions on the Y chromosome, which would also explain why the genes appear to be in order on the X but scrambled on the Y," Page explains. (abc.net.au)
  • mutations
  • Finally, we use our unique 30-year ecological dataset and rich collection of DNA samples of the great reed warbler to test the widely accepted but poorly supported sexual antagonism hypothesis suggesting that sexually antagonistic mutations accumulate on the sex chromosomes and drive their evolution. (lu.se)
  • To understand the interplay between sex chromosomes and sexual conflicts by studying whether sexually antagonistic mutations accumulate on sex chromosomes, and whether sexual conflicts drive sex chromosome evolution. (lu.se)
  • However, in a ZW system one can separate the effect of the hemizygous chromosome from the male-biased mutations, providing an excellent system for understanding the evolution of SCD. (royalsocietypublishing.org)
  • They then compared the number of mutations between the X form and the Y form of a pair of X-Y genes to come up with rough estimates of when they were last alike, giving them a 'geologic' snapshot of sex chromosomes. (abc.net.au)
  • tumor
  • These results suggest that a senescence gene or genes, which may be located on the Chinese hamster X chromosome, can be regulated by DNA methylation, and that escape from senescence and possibly loss of tumor suppressor gene activity can occur by epigenetic mechanisms. (sciencemag.org)
  • exhibit
  • In particular, females with Turner's syndrome (TS) who have only one X-chromosome exhibit deficits of spatial ability whereas males with Klinefelter's syndrome (KS) who possess a supernumerary X-chromosome are delayed in acquiring words. (ox.ac.uk)
  • Genetic
  • This lack of detailed knowledge about sex chromosome evolution compromises our understanding of fundamental biological questions (e.g. the evolution of sexual conflicts) as well as more practical ones (e.g. about sex-linked genetic diseases). (lu.se)
  • discovery
  • Ever since their discovery, these chromosomes have captivated researchers because of their obvious involvement in fundamental aspects of an organism's life, such as sex determination, sexual reproduction and sexual conflicts. (lu.se)
  • found
  • The X chromosome was found to have four groups of genes physically arranged as four consecutive blocks, like the layers of rock in geological strata. (abc.net.au)
  • development
  • The findings suggest that the number of sex chromosomes influences the development of brain asymmetry not simply to modify the torque but in a complex pattern along the antero-posterior axis. (ox.ac.uk)
  • events
  • The first events that created the sex chromosomes had been thought to have occurred at least 170 million years ago," says researcher Dr David Page. (abc.net.au)
  • By fossil digging on the sex chromosomes, we were able to reconstruct the four events that drove sex chromosomes into their distinctive X and Y forms, and to date when these events occurred during evolution," says Lahn. (abc.net.au)
  • cells
  • In a second project, we focus on what moves chromosomes when cells divide. (omrf.org)
  • Transfer of a normal Chinese hamster X chromosome (carried in a mouse A9 donor cell line) to a nickel-transformed Chinese hamster cell line with an Xq chromosome deletion resulted in senescense of these previously immortal cells. (sciencemag.org)
  • At early passages of the A9/CX donor cells, the hamster X chromosome was highly active, inducing senescence in 100% of the colonies obtained after its transfer into the nickel-transformed cells. (sciencemag.org)
  • However, senescence was reduced to 50% when Chinese hamster X chromosomes were transferred from later passage A9 cells. (sciencemag.org)
  • Full senescing activity of the intact hamster X chromosome was restored by treatment of the donor mouse cells with 5-azacytidine, which induced demethylation of DNA. (sciencemag.org)
  • research
  • Research published in this week's Science reveals that the Y chromosome developed from an X-like ancestor around 300 million years ago. (abc.net.au)
  • women
  • Specifically, we tested Crow's prediction that the magnitude of the brain torque (i.e., a combination of rightward frontal and leftward occipital asymmetry) would, as a function of sex chromosome dosage, be respectively decreased in TS women and increased in KS men, relative to genotypically normal controls. (ox.ac.uk)