Evolution versus constitution: differences in chromosomal inversion.
We compared the chromosomal breakpoints of evolutionary conserved and constitutional inversions. Multicolor banding and human-specific bacterial artificial chromosomes were applied to map the breakpoints of constitutional pericentric inversions on human chromosomes 2 and 9. For the first time, we present a high-resolution analysis of the breakpoint regions, which are characterized by gene destitution, co-localization with fragile sites, multitude repeats as well as pseudogenes and, remarkably, a large sequence homology to the opposite breakpoint. In contrast, evolutionary inversion breakpoints lack such extensive cross-hybridizing regions and are often associated with fragile sites of the genome and low-copy repeats. These molecular characteristics gave evidence for different types of inversion formation and indicate that evolutionary inversions cannot originate from constitutional inversions like those of chromosomes 2 and 9. Finally, the constitutional inversion breakpoints were investigated on three different great ape species and on four test persons each bearing the same cytogenetically determined inversion on chromosomes 2 and 9, respectively. Our data indicate the existence of different molecular breakpoints for the two variant chromosomes.
Schmidt
S
S
Institute of Human Genetics and Anthropology, 07740 Jena, Germany.
Claussen
U
U
Liehr
T
T
Weise
A
A
D000818:Animals; D007446:Chromosome Inversion / Q000235:genetics*; D002874:Chromosome Mapping; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D002889:Chromosomes, Human, Pair 2 / Q000235:genetics*; D002899:Chromosomes, Human, Pair 9 / Q000235:genetics*; D019143:Evolution, Molecular; D015186:Hominidae / Q000235:genetics; D006801:Humans