Note that X:A and Y:A depend only on the ratio between mutation rates on different chromosomes, not the absolute mutation rate. We also compared our estimates of sex chromosome diversity to predictions from coalescent theory Pool and Nielsen ; Polanski et al.
J Roy Stat Soc D.
An extra copy of the genes contained in the pseudoautosomal region of the Y chromosome may explain the tall stature and other features that can affect same y-chromosome sex linked traits in Beaumont and men with this condition.
GATA simple sequence repeats function as enhancer blocker boundaries. Only one of the three genes that rejected the CLR test on the ancestral X chromosome were consistent with a selective sweep model using the GOF test, whereas 13 of the 19 neo-X genes rejecting the CLR test were consistent with same y-chromosome sex linked traits in Beaumont recent selective sweep Table 1.
Deletions of small amounts of genetic material in certain areas of the Y chromosome lead to a condition called Y chromosome infertility. We use total tree length as an estimator of expression divergence.
To evaluate these effects, we further subdivided genic sites according to gene-expression patterns inferred from two expression data sets, one in 18 adult tissues and one a time course across spermatogenesis see Materials and Methods.
Biol Sex Differ 6, 6 Table S3. The Y-chromosome tree otherwise shows perfect concordance between clades and geographic locations. Many genes are unique to the Y chromosome, same y-chromosome sex linked traits in Beaumont genes in areas known as pseudoautosomal regions are present on both sex chromosomes.
Recent positive selection results not only in a local reduction of variation in the genomic region surrounding the target of selection, but also in a skew in the frequency distribution of mutations surrounding the target of selection i. B Observed site frequency spectra by population, with fitted spectra from the four models in panel A.
Analyses of autosomes used both males and females from each population; sex chromosome analyses used males only to avoid introducing technical artifacts associated with differences in sample ploidy. Influence of partial deletion of the Y chromosome on mouse sperm phenotype. Future investigations into the genetic and molecular mechanisms that establish ChrY as a member of the regulatory genome in males, and as a factor influencing paternal POO effects in female offspring, will be aided by the sequencing efforts put forth for mammalian ChrYs [ - ], especially mouse [ 10 ].
Reduction in Sex-Linked Diversity Is Inconsistent with Simple Demographic Models Sex chromosomes are affected differently than autosomes by both neutral forces, such as changes in population size Pool and Nielsen , and by natural selection reviewed in, e. A Y chromosome-linked factor impairs NK T development.
As a result of such a fusion, one chromosome—the neo-Y—is cotransmitted with the Y chromosome through males only.