Molecular cytogenetics provides a visual, pictorial record of the tree of life, and in this respect the fusion origin of human chromosome 2 is a well known paradigmatic example. Here we report on a variant chromosome 6 in which the centromere jumped to 6p22.1. ChIP-on-chip experiments with antibodies against the centromeric proteins CENP-A and CENP-C exactly defined the neocentromere as lying at chr6:26,407-26,491 kb. We investigated in detail the evolutionary history of chromosome 6 in primates and found that the Primate ancestor had a homologous chromosome with the same marker order, but with the centromere located at 6p22.1. Sometime between 17-23 million years ago, in the common ancestor of humans and apes, the centromere of chromosome 6 moved from 6p22.1 to its current location. The neocentromere we discovered, consequently, has jumped back to the ancestral position where a latent centromere-forming potentiality persisted for at least 17 mya. Because all living organisms form a tree of life, as firstly conceived by Darwin, evolutionary perspectives can provide compelling underlying explicative grounds for contemporary genomic phenomena.
Evolutionary descent of a human chromosome 6 neocentromere: a jump back to 17 million years ago.
PURGATO, STEFANIA;DELLA VALLE, GIULIANO;
2009
Abstract
Molecular cytogenetics provides a visual, pictorial record of the tree of life, and in this respect the fusion origin of human chromosome 2 is a well known paradigmatic example. Here we report on a variant chromosome 6 in which the centromere jumped to 6p22.1. ChIP-on-chip experiments with antibodies against the centromeric proteins CENP-A and CENP-C exactly defined the neocentromere as lying at chr6:26,407-26,491 kb. We investigated in detail the evolutionary history of chromosome 6 in primates and found that the Primate ancestor had a homologous chromosome with the same marker order, but with the centromere located at 6p22.1. Sometime between 17-23 million years ago, in the common ancestor of humans and apes, the centromere of chromosome 6 moved from 6p22.1 to its current location. The neocentromere we discovered, consequently, has jumped back to the ancestral position where a latent centromere-forming potentiality persisted for at least 17 mya. Because all living organisms form a tree of life, as firstly conceived by Darwin, evolutionary perspectives can provide compelling underlying explicative grounds for contemporary genomic phenomena.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
