Molecular evolution of NR0B1 (DAX1) and related genes in mammals.

摘要

Here, we study the molecular evolution of NR0B1 (DAX1) and genes related by function structure, or location. We have compared NR0B1 (DAX1) with the sex determination genes SRY and SOX9, with other members of the nuclear hormone receptor superfamily, including the NR0B subfamily member NR0B2 (SHP), and with other X linked gene X-Y gene pairs. Chapter One compares the molecular evolution of SRY, NR0B1 , and SOX9 in closely related primate species. According to several measures, we found DAX1 evolved in a fashion intermediate between SRY and SOX9: overall measures gene and protein similarity were closer for NR0B1 and SOX9, but NR0B1 exhibited nonsynonymous amino acid substitutions at an accelerated frequency relative to synonymous changes, similar to SRY and significantly higher than SOX9 . Chapter addresses the evolution of NR0B1 and other nuclear receptor (NR) superfamily in human and mouse. We compared NR0B1 with 34 other NR members from all seven subfamilies, and with genes related to NR0B1 by function (SOX9) or chromosomal location (SOX3 and GK), to determine if NR0B1 exhibited molecular evolutionary properties similar to any of these related genes. The Ka and Ks values were calculated in pairwise comparisons for genes between species. Codon usage and GC content at silent sites of synonymous codons (GC3s) were compared. We also performed Correspondence Analysis on codon usage for these genes in human and mouse. Chapter Three considers the evolution of NR0B1 (DAX1) relative to X-linked genes and X-Y gene pairs in human and mouse. We compared NR0B1 sequence changes during evolution with other X-linked genes and X-Y gene pairs to determine if evolutionary profiles could be correlated with chromosomal location. Here, we have undertaken a comparative genomics approach to the study of related genes. We suggest that interspecific comparisons addressing the molecular evolution of genes may reveal important properties related to functional roles and constraints at the protein level.