title: Analysis of compensatory substitution and gene evolution on the MAGEA/CSAG-palindrome of the primate X chromosomes.
abstract: The human X chromosome contains a large number of inverted repeat DNA palindromes. Although arbitrary substitutions destroyed the inverted repeat structure of MAGEA/CSAG-palindrome during the evolutionary process of the primates, most of the substitutions are compensatory. Using maximum parsimony, it is demonstrated that the compensatory substitutions are prone to occur between bases with similar structures on the human, chimpanzee and orangutan MAGEA/CSAG-palindromes. Furthermore, it is found that MAGEA/CSAG genes also exist in orangutan and rhesus monkey palindromes by homologous searching. This suggests that the MAGEA/CSAG-palindrome might predate the divergence of human and other primate lineages. Comparative sequence analysis of the arms and genes on the primate MAGEA/CSAG-palindromes provides possible evidence of subsequently arm to arm gene conversion. These compensatory substitutions on the MAGEA/CSAG-palindrome of the primate X chromosomes play an important role in maintaining their structural symmetry during the process of formation.
authors.affiliation: Department of Chemical Engineering, Northwest University for Nationalities, Lanzhou 730124, PR China. qiajiao@163.com
authors.forename: Yanjiao
authors.initials: Y
authors.lastname: Qi
authors.forename: Huining
authors.initials: H
authors.lastname: Lu
authors.forename: Duiyuan
authors.initials: D
authors.lastname: Ai
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics; D004247:DNA / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D006801:Humans; D055029:Inverted Repeat Sequences / Q000235:genetics*; D058950:Melanoma-Specific Antigens / Q000235:genetics; D009363:Neoplasm Proteins / Q000235:genetics; D010802:Phylogeny; D011323:Primates / Q000235:genetics*; D014960:X Chromosome / Q000235:genetics*
chemical_list: D000951:Antigens, Neoplasm; C457202:CSAG1 protein, human; C072011:MAGEA1 protein, human; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins; D004247:DNA