Origins of primate chromosomes – as delineated by Zoo-FISH and alignments of human and mouse draft genome sequences

Abstract

This review examines recent advances in comparative eutherian cytogenetics, including Zoo-FISH data from 30 non-primate species. These data provide insights into the nature of karyotype evolution and enable the confident reconstruction of ancestral primate and boreo-eutherian karyotypes with diploid chromosome numbers of 48 and 46 chromosomes, respectively. Nine human autosomes (1, 5, 6, 9, 11, 13, 17, 18, and 20) represent the syntenies of ancestral boreo-eutherian chromosomes and have been conserved for about 95 million years. The average rate of chromosomal exchanges in eutherian evolution is estimated to about 1.9 rearrangements per 10 million years (involving 3.4 chromosome breaks). The integrated analysis of Zoo-FISH data and alignments of human and mouse draft genome sequences allow the identification of breakpoints involved in primate evolution. Thus, the boundaries of ancestral eutherian conserved segments can be delineated precisely. The mapping of rearrangements onto the phylogenetic tree visualizes landmark chromosome rearrangements, which might have been involved in cladogenesis in eutherian evolution.

Reconstruction and evolutionary history of eutherian chromosomes

“…We compared the eutherian, boreoeutherian, and simian ancestral karyotypes determined by FISH (6,8,20) with those obtained using DESCHRAMBLER and three additional tools (see Materials and Methods for details). In this evaluation, we focused on interchromosomal rearrangements using human chromosomes as a reference.…”

High-resolution comparative chromosome painting in the Arizona collared peccary (Pecari tajacu, Tayassuidae): a comparison with the karyotype of pig and sheep

“…Obviously, representatives of later branches, such as the Ruminantia and especially the Cetacea (i.e. whales and dolphins) conserved much more of the ancestral karyotype of all placental mammals, while early Suiformes experienced drastic reshuffling of their karyotype (Bielec et al 1998, Froenicke & Wienberg 2001, Biltueva et al 2004, Froenicke 2005. Bovid karyotypes, although changed by many centromeric fissions, conserved most motifs in chromosome morphology, that can easily be reconstructed from the ancestral karyotype of all cetartiodactyls and even from that of most other mammals (Chowdhary et al 1998, Froenicke 2005.…”

“…whales and dolphins) conserved much more of the ancestral karyotype of all placental mammals, while early Suiformes experienced drastic reshuffling of their karyotype (Bielec et al 1998, Froenicke & Wienberg 2001, Biltueva et al 2004, Froenicke 2005. Bovid karyotypes, although changed by many centromeric fissions, conserved most motifs in chromosome morphology, that can easily be reconstructed from the ancestral karyotype of all cetartiodactyls and even from that of most other mammals (Chowdhary et al 1998, Froenicke 2005. Froenicke & Wienberg (2001) used sheep chromosome paints on pig chromosomes for a high-resolution cytogenetic map between these two artiodactyl species and revealed numerous inter-chromosomal rearrangements that should have occurred in suid phylogeny.…”

“…Over the past 15 years chromosome painting has been extensively used in cytotaxonomy and phylogenetic studies (see recent reviews by Wienberg 2004, Froenicke 2005). When hybridizing fluorochrome-labeled chromosome-specific DNA probes of one species to the chromosomes fixed on slides of another species, homologies can be identified at the microscope between both species that are based on homologous DNA sequences.…”

Molecular refinement of gibbon genome rearrangements

“…Most evolutionary chromosomal rearrangements between ape lineages involve pericentric (including the centromere) or paracentric (not including the centromere) inversions (Yunis and Prakash 1982). In contrast, comparative studies of gibbons (small apes, family Hylobatidae) indicate that the karyotypes of all 12 (or more) species appear highly derived, with an unusually large number (n > 40) of chromosomal fissions and translocations (Jauch et al 1992;Koehler et al 1995a,b;Muller and Wienberg 2001;Murphy et al 2001;Nie et al 2001;Muller et al 2002Muller et al , 2003Ferguson-Smith et al 2005;Froenicke 2005). Their chromosomal numbers range from 2n = 38 (hoolock gibbons) to 2n = 52 (Nomascus) and differ from other ape lineages in showing an accelerated rate of chromosomal translocation during evolution.…”