Recruitment of old genes to new functions: evidences obtained by comparing the orthologues of human XLMR genes in mouse and chicken.
Gene mapping data indicate that the human X chromosome is enriched in genes that affect both, higher cognitive efficiency and reproductive success. This raises the question whether these functions are ancient, or whether conserved X-linked genes were recruited to new functions. We have studied three X-linked mental retardation (XLMR) genes by RNA in situ hybridization in mouse and in chicken, in which these genes are autosomal: Rho guanine nucleotide exchange factor 6 (ARHGEF6), oligophrenin (OPHN1), and p21 activated kinase 3 (PAK3). In the mouse these genes are specifically expressed in telencephalic regions. Their orthologues in the chicken gave patterns of similar specificity in ancient parts of the brain, i.e. cerebellum and mesencephalon, but were not expressed in the telencephalon. Also in the testes, specific expression was only found in mouse, not in chicken. These data are interpreted such that certain genes on the X chromosome gained novel functions during evolution.
Kohn
M
M
Institut fur Humangenetik, Universitat Ulm, Ulm, Germany.
Kehrer-Sawatzki
H
H
Steinbach
P
P
Marshall Graves
J A
JA
Hameister
H
H
D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism; D002645:Chickens / Q000235:genetics*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D050172:Genes, X-Linked / Q000235:genetics*; D006801:Humans; D008297:Male; D038901:X-Linked Intellectual Disability / Q000235:genetics*; D051379:Mice / Q000235:genetics*; D008810:Mice, Inbred C57BL; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012689:Sequence Homology, Nucleic Acid; D013737:Testis / Q000166:cytology / Q000378:metabolism
D012333:RNA, Messenger