A similar pattern is observed in platypus, although these results are less clear due to the relatively low number of X 5 -linked genes that could be analyzed Figure S Reciprocal chromosome painting shows that Oan X 5 and Tac X 4 are homologous. Similarly, homologous regions were not determined for short regions on Tac 3p, 4p, 5p, 6p, 8p, 13p, 15q, 16p, 17q, 18, 20, 21, 23, 24p and the large regions on 1q and 2q.
In the first analysis, we defined sets of genes specifically expressed in a given tissue in the following way. The two sex chromosomes are considered autosomes chromosomes in Adelaide You, these observations suggest that the excess of testis specificity observed for the X is driven by new genes that accumulated on this chromosome after sex chromosome differentiation, potentially due to the emerging sex-related selective forces .
So far, no chicken Z genes have been mapped to platypus X 4but this may not be surprising as X 4 is homologous to an echidna autosome.
PLoS Biol 6: e External link. The chromosome paints were used to identify autosome pairs and sex chromosomes in male and female echidnas. This index value can thus range from 0 no expression in that tissue and expression in at least one other tissue to 1 only expressed in that tissue.
These are XX in females and XY in males. Thank you for your feedback. Main article: Nucleoid. Last updated: August 13,
Received Apr 16; Revised Aug 2. These results confirm and extend the homology between platypus chromosome 6 and the human X that was previously established for seven XCR genes Waters et al. Nov 02, Distributions of expression levels of proto X-linked genes blue line and proto autosomal genes red line are shown for cerebellum and liver from opossum.