The Ancestral Carnivore Karyotype (2n = 38) Lives Today in Ringtails

Abstract

Chromosome painting was used to investigate the conservation of high-resolution longitudinal 4',6-diamidino-2-phenylindole (DAPI)/G bands in Carnivore chromosomes. Cat (Felis catus) and raccoon dog (Nyctereutes procyonoides) painting probes were hybridized to the ringtail (Bassaricus astutus), dwarf mongoose (Helogale parvula), and Malagasy civet (Fossa fossa) to identify homologous chromosome elements. The patterns of chromosome segment homology among Carnivore species allowed us to reconstruct and propose the disposition of a high-resolution banded ancestral carnivore karyotype (ACK). Three bi-armed chromosomes consistently found among Caniformia species are represented as 6 homologous acrocentric chromosomes among Feliformia species of Carnivora. However, reexamination of the most basal of Feliformia species, the African palm civet Nandinia, revealed the presence of the 3 heretofore Caniformia bi-armed chromosomes. Because these 3 bi-armed chromosomes are found in both Caniformia and Feliformia lineages, they are presumed ancestral for all Carnivora, suggesting that the ACK chromosome number would be 38, rather than the previously supposed 42. Banded chromosomes of the ACK are used to evaluate the consistency between recently determined molecular phylogenetic relationships and postulated cytogenetic dynamics in the same Carnivore species.

Comparative Chromosome Painting in Carnivora and Pholidota

“…The ancestral karyotype of Carnivora has been described or discussed several times [Wurster-Hill and Gray, 1975;Dutrillaux and Couturier, 1983;Fronicke et al, 1997;Murphy et al, 2001b;Nash et al, 2008;Perelman et al, 2008;Nie et al, 2012]. Table 3 provides the correspondence of ACK chromosomes with feline ( Felis catus , FCA), dog ( Canis familiaris , CFA), stone marten ( Martes foina , MFO) and human ( Homo sapiens , HSA) chromosomes as well as with previously suggested ancestral carnivore karyotypes.…”

“…Number of symbols on each branch indicates the number of fragments of the particular chromosome in the karyotype. Fronicke et al, 1997;Nash et al, 2008]. However, the discussion about whether the fission or fusion of ACK1 represents the ancestral state will not be settled until chromosome painting is done to verify the G-banding data or until another species is identified with FCA A2p+C2 as 1 chromosome within the Feliformia branch.…”

“…Only 2 representatives of Procyonidae, both from the subfamily Procyoninae (Procyon lotor and Bassariscus astutus) , have been studied by chromosome painting [Nash et al, 2008;Perelman et al, 2008]. Their karyotypes differ only by 1 inversion, revealed by dog painting probes (ACK13) [Nie et al, 2012], but otherwise they represent well the ancestral musteloid karyotype (AMK).…”

“…In this regard it would be important to study other species from the subfamily, such as those from genera Poiana and Viverra . Other Feliformes Based on 2 species studied so far, there are 5 common fusions characteristic for Herpestidae (ACK11+9, 17+8, 15+7q, 20+10, 7p+1p) [Nash et al, 2008;Nie et al, 2012]. This large family requires more species to be studied by chromosome painting.…”

Satellite DNA Sequences in Canidae and Their Chromosome Distribution in Dog and Red Fox

“…It has been generally accepted that the ancestral carnivore karyotype consists of a relatively low number (2n = 38) of chromosomes [Graphodatsky et al, 2001;Nash et al, 2008;Beklemisheva et al, 2016]. The subsequent karyotype evolution in Canidae occurred by multiple breakage-fusion events including also whole-arm inversions and resulted in a variety of species extensively dif- All sequences lacked any satellite DNA using RepeatMasker.…”