The 200-kb segmental duplication on human chromosome 21 originates from a pericentromeric dissemination involving human chromosomes 2, 18 and 13.
Regions close to human centromeres contain DNA fragments spanning hundreds of kilobases that exhibit a high degree of sequence identity (>95%). Here we report the genomic structure and evolution of a family of four paralogous regions related to a 220-kb genomic fragment present on the long arm of human chromosome 21 (21q22.1). Phylogenetic classification of the paralogous sequences obtained from the draft of the Human Genome Project are in agreement with results from comparative fluorescence in situ hybridization on metaphase chromosomes from human and great apes. The original copy present in 21q22.1 in human was duplicated in great apes after the divergence of the orang-utan and inserted in a pericentromeric region, most likely the ancestor of HSA2q, then disseminated by transposition of a larger fragment to other pericentromeric locations: HSA18p11, HSA13q11 and HSA21q11.1. The degree of dissemination varies among species.
Golfier
Geoffroy
G
Neurobiologie et Diversité Cellulaire, CNRS UMR7637, Ecole Supérieure de Physique et Chimie Industrielles, 10 rue Vauquelin, 75005 Paris, France.
Chibon
Frédéric
F
Aurias
Alain
A
Chen
Xiao-Ning
XN
Korenberg
Julie
J
Rossier
Jean
J
Potier
Marie-Claude
MC
D000818:Animals; D002869:Chromosome Aberrations; D002882:Chromosomes, Human, Pair 13 / Q000235:genetics; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics; D002889:Chromosomes, Human, Pair 2 / Q000235:genetics; D002891:Chromosomes, Human, Pair 21 / Q000235:genetics*; D020440:Gene Duplication; D015894:Genome, Human; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D019974:Pan paniscus / Q000235:genetics; D010802:Phylogeny