Karyological analysis of Proechimys cuvieri and Proechimys guyannensis (Rodentia, Echimyidae) from central Amazon

Abstract

The aim was to characterize the karyotype of rodents of the genus Proechimys from three localities in the central Brazilian Amazon, in the search for new markers that might shed light on our understanding of the taxonomy and evolutionary history of this taxon. Two karyotypes were found, viz., 2n = 28, FN = 46 in individuals from the NRSP (Cuieiras River) and REMAN (Manaus), and 2n = 46, FN = 50 in individuals from the Balbina Hydroelectric Plant. While individuals with the karyotype with 2n = 28 chromosomes were morphologically associated with Proechimys cuvieri, their karyotype shared similarities with those of the same diploid number in two other regions. Although three karyotypes are described for Proechimys cuvieri, no geographic distribution pattern that defined a cline could be identified. Based on the morphological examination of voucher specimens and additional results from molecular analysis, the karyotype with 2n = 46 and FN = 50 could be associated with P. guyannensis.

Peer Review #1 of "Cytogenetic analyses in Trinomys (Echimyidae, Rodentia), with description of new karyotypes (v0.2)"

“…6). A chromosome pair with a large secondary constriction bearing the single NOR is a marker of echimyids, as already reported for T. iheringi and other Echimyidae genera (Fagundes, Camacho & Yonenaga-Yassuda, 2004;Silva et al, 2012;Araújo et al, 2014). The comparison of the GTG-banded karyotypes suggests that the NOR-bearing chromosome is the same in our specimens and in T. albispinus, T. iheringi, and T. yonenagae PeerJ reviewing PDF | (2018:02:25803:2:0:CHECK 2 Jul 2018)…”

Cytogenetic analyses in Trinomys (Echimyidae, Rodentia), with description of new karyotypes

“…6 ). A chromosome pair with a large secondary constriction bearing the single NOR is a marker of echimyids, as already reported for T. iheringi and other Echimyidae genera ( Fagundes, Camacho & Yonenaga-Yassuda, 2004 ; Silva et al, 2012 ; Araújo et al, 2014 ). The comparison of the GTG-banded karyotypes suggests that the NOR-bearing chromosome is the same in our specimens and in T. albispinus, T. iheringi, and T. yonenagae ( Leal-Mesquita et al, 1992 ; Fagundes, Camacho & Yonenaga-Yassuda, 2004 ) and is probably conserved in the genus .…”

New karyotype records for the genus Proechimys (Rodentia: Echimyidae) from Brazilian Amazonia

“…Seven cytotypes have been described for the guyannensis group (sensu Patton, 1987), with diploid numbers of 30, 38, 40, and 46 chromosomes (Machado et al, 2005;Eler et al, 2012;Silva et al, 2012). The 2n = 46 cytotype is found in central Brazilian Amazonia, on the left margin of the Amazon River, in the region between the Uatumã River, in Amazonas state, São João da Baliza, in Roraima, and the lower Trombetas River, in Pará (Figure 5), where it is sympatric with P. cuvieri.…”

“…The three known P. cuvieri karyotypes (2n = 28 and FN = 46, FN = 48, and FN = 50) include three pairs of chromosomes that are significantly larger than all the others of the complement, together with at least one submetacentric pair (Maia and Langguth, 1993;Patton et al, 2000;Silva et al, 2012). The individuals from the Japurá River analyzed here (2n = 28, FN = 46) are distinct 6 Eler et al from all other representatives of this species in having only two pairs (1 and 10) of large chromosomes and no submetacentric chromosomes, with a relatively larger number of acrocentrics, in comparison with the karyotypes described previously.…”

“…In the family Echimiydae, the mapping of repetitive DNA sequences is limited to the location of the 45S rDNA and telomeric sequences in six species: Phyllomys lamarum and Phyllomys sp. from northern Minas Gerais, Brazil (Araújo et al, 2014); and Proechimys guyannensis, Proechimys cuvieri (Silva et al, 2012), Proechimys longicau-datus (Amaral et al, 2013), and two cytotypes of P. goeldii (Rodrigues da Costa et al, 2016), collected in Brazilian Amazonia.…”