Hominoid fission of chromosome 14/15 and the role of segmental duplications.
Ape chromosomes homologous to human chromosomes 14 and 15 were generated by a fission event of an ancestral submetacentric chromosome, where the two chromosomes were joined head-to-tail. The hominoid ancestral chromosome most closely resembles the macaque chromosome 7. In this work, we provide insights into the evolution of human chromosomes 14 and 15, performing a comparative study between macaque boundary region 14/15 and the orthologous human regions. We construct a 1.6-Mb contig of macaque BAC clones in the region orthologous to the ancestral hominoid fission site and use it to define the structural changes that occurred on human 14q pericentromeric and 15q subtelomeric regions. We characterize the novel euchromatin-heterochromatin transition region (∼20 Mb) acquired during the neocentromere establishment on chromosome 14, and find it was mainly derived through pericentromeric duplications from ancestral hominoid chromosomes homologous to human 2q14-qter and 10. Further, we show a relationship between evolutionary hotspots and low-copy repeat loci for chromosome 15, revealing a possible role of segmental duplications not only in mediating but also in "stitching" together rearrangement breakpoints.
Dipartimento di Biologia, Università degli Studi di Bari "Aldo Moro," Bari 70125, Italy;
Giuliana
G
Giannuzzi
Michele
M
Pazienza
John
J
Huddleston
Francesca
F
Antonacci
Maika
M
Malig
Laura
L
Vives
Evan E
EE
Eichler
Mario
M
Ventura
D000818:Animals; D056905:Chromosome Breakpoints; D058674:Chromosome Duplication; D022202:Chromosomes, Artificial, Bacterial; D002883:Chromosomes, Human, Pair 14 / Q000235:genetics*; D002884:Chromosomes, Human, Pair 15 / Q000235:genetics*; D033481:Chromosomes, Mammalian / Q000235:genetics*; D003001:Cloning, Molecular; D022041:Euchromatin / Q000235:genetics; D019143:Evolution, Molecular; D006570:Heterochromatin / Q000235:genetics; D015186:Hominidae / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D010802:Phylogeny; D056916:Segmental Duplications, Genomic
D022041:Euchromatin; D006570:Heterochromatin