Comparative molecular cytogenetic studies in the order Carnivora: mapping chromosomal rearrangements onto the phylogenetic tree

Abstract

We have made a set of chromosome-specific painting probes for the American mink by degenerate oligonucleotide primed-PCR (DOP-PCR) amplification of flow-sorted chromosomes. The painting probes were used to delimit homologous chromosomal segments among human, red fox, dog, cat and eight species of the family Mustelidae, including the European mink, steppe and forest polecats, least weasel, mountain weasel, Japanese sable, striped polecat, and badger. Based on the results of chromosome painting and G-banding, comparative maps between these species have been established. The integrated map demonstrates a high level of karyotype conservation among mustelid species. Comparative analysis of the conserved chromosomal segments among mustelids and outgroup species revealed 18 putative ancestral autosomal segments that probably represent the ancestral chromosomes, or chromosome arms, in the karyotype of the most recent ancestor of the family Mustelidae. The proposed 2n = 38 ancestral Mustelidae karyotype appears to have been retained in some modern mustelids, e.g., Martes, Lutra, Ictonyx, and Vormela. The derivation of the mustelid karyotypes from the putative ancestral state resulted from centric fusions, fissions, the addition of heterochromatic arms, and occasional pericentric inversions. Our results confirm many of the evolutionary conclusions suggested by other data and strengthen the topology of the carnivore phylogenetic tree through the inclusion of genome-wide chromosome rearrangements.

A meiotic linkage map of the silver fox, aligned and compared to the canine genome

“…These results agree with the previous comparative cytogenetic map of the dog and fox (Yang et al 1999). The orientation of blocks corresponding to dog chromosomes 22, 27, 35, 36, and a fragment of CFA19 on the fox meiotic map was reversed compared to the orientation reported in previous cytogenetic studies (Graphodatsky et al 2002).From the analysis of marker order on homologous dog and fox chromosomes, the comparative orientation in terms of telomere to centromere direction, or reverse, could be examined. In several cases the orientation of dog chromosomes and corresponding fox chromosomal arms was concordant (for example, CFA8 and one arm of VVU6, CFA14 and one arm of VVU7; Fig.…”

“…These results agree with the previous comparative cytogenetic map of the dog and fox (Yang et al 1999). The orientation of blocks corresponding to dog chromosomes 22, 27, 35, 36, and a fragment of CFA19 on the fox meiotic map was reversed compared to the orientation reported in previous cytogenetic studies (Graphodatsky et al 2002).…”

“…Dog chromosomes which have their homologs divided among more than one fox chromosome are marked by asterisks (*) (see VVU1, 2, 4, 5, and 13). Dog chromosomal segments for which the orientation on the fox meiotic map was reversed compared to the orientation reported in previous cytogenetic studies (Graphodatsky et al 2002) are marked by dots (᭹) (see VVU3, 4, 6, 8, and 12). Centromere positions of dog chromosomes are indicated in accordance with the dog genome sequence, assuming that the centromere is located at the beginning of each chromosome.…”

Cytogenetic study of the giant otter Pteronura brasiliensis Zimmermann 1780 (Carnivora, Mustelidae, Lutrinae)

“…Nie et al (2002) used chromosomal rearrangements, a rare type of genomic change, to investigate some systematic questions relating to the genome phylogeny of the domestic cat, red panda and five mustelid species. However, while cytogenetic studies have previously been carried out on other mustelid species (Freitas et al, 1975;Kurose et al, 2000;Graphodatsky et al, 2002) there have been no published studies on the chromosomal constitution of P. brasiliensis.In this paper we describe for the first time the karyotype of P. brasiliensis, providing valuable data to verify the validity of the alleged subspecies in future studies using specimens from the Pantanal region.We carried out chromosomal analyses on two male and two female giant otters from the Brazilian Amazon basin held in captivity at the Aquatic Mammals Laboratory of the National Institute for Amazonian Research (Instituto Nacional de Pesquisas da Amazônia, INPA), Manaus, Amazonas, Brazil (Figure 1). The giant otters were sedated with 1.93 ± 0.57 mg kg -1 of Zoletil ® (Virbac, Brazil) and Genetics and Molecular Biology, 30, 4, 1093-1096 (2007 Short Communication blood samples collected from the femoral vein using an heparinized syringe which was maintained in a vertical position for 30 min after collection to allow the lymphocytes to separate.…”

Reconstructing large regions of an ancestral mammalian genome in silico

“…On a smaller scale, such ancestral reconstructions have been performed for protein families including rhodopsin (Chang et al 2002), ultraviolet vision gene SWS1 (Shi and Yokoyama 2003), ribonucleases (Jermann et al 1995;Zhang and Rosenberg 2002), Tu elongation factors (Gaucher et al 2003), steroid receptors (Thornton et al 2003) (for review, see Chang and Donoghue 2000;Thornton 2004), for transposons (Adey et al 1994;Smit and Riggs 1996;Ivics et al 1997;Jurka 2000), and for small genomes like HIV (Hillis et al 1994), in which case the predicted ancestral sequences were compared with the known ones. However, studies of large-scale computational genome reconstruction, an undertaking that might be termed computational "paleogenomics" (Birnbaum et al 2000), have been limited to higher-level genome properties such as gene order (Blanchette et al 1999;El-Mabrouk and Sankoff 1999;Pevzner and Tesler 2003;Bourque et al 2004) or karyotype (Graphodatsky et al 2002;.…”