Eler ES et al. (2020), New karyotype records for the genus Proechimys ...

ECB-ART-49802

Genet Mol Biol 2020 Jun 01;433:e20190093. doi: 10.1590/1678-4685-GMB-2019-0093.

Show Gene links Show Anatomy links

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

Eler ES , Silva CEF , Silva MNF , Feldberg E .

???displayArticle.abstract???
We present new karyotype records for six Proechimys species from the Brazilian Amazon. P. echinothrix from the region of Purus River had 2n = 32 chromosomes and a FN = 58, while P. cuvieri from the region of the Japurá River presented 2n = 28 and FN = 46. All individuals presented hybridization with an 18S rDNA probe in a single chromosome pair, with the exception of P. cuvieri from the Japurá region, which presented a third signal in one of the homologs of pair 1. No ITS were found in any of the individuals. Our data supports the hypothesis that the P. cuvieri population from the Japurá Basin and P. echinothrix from the lower Purus are new taxonomic entities. Our data expand the geographic distribution of the cytotype (2n = 40, FN = 54) described for P. gardneri from the Madeira River, and the cytotype (2n = 46, FN = 50), described for P. guyannensis, as well as the recently-described cytotype of P. goeldii (2n = 16, FN = 14). No clear pattern of chromosomal evolution has yet been defined in Proechimys, despite the considerable karyotypic diversity of the genus.

???displayArticle.pubmedLink??? 32484848
???displayArticle.pmcLink??? PMC7265155
???displayArticle.link??? Genet Mol Biol

???attribute.lit??? ???displayArticles.show???

	Figure 1. Map of the Brazilian Amazon basin, indicating the collection locations of Proechimys specimens. 1 - left bank of up Japurá River (1.84341666667°S, −69.0264722222°W); 2 - Santa Isabel do Rio Negro, Negro River (0.57725000000°S, 64.8976944444°W); 3 - Extractive Reserve of Canutama, Purus River (6.5784111000°S, 64.5723388900°W); 4 - lower Jacinto River, right bank of Purus River (6.8300640000°S; 64.2819020000°W); 5 - Rebio Abufari, left bank of Purus River (4.97616666667°S; 62.9774722222°W); 6 – Left bank of Madeira River (4.97616666667ºS, 62.9774722222ºW); 7 - lower Aripuanã River (6.00000000000° S, 60.1666666667°W); 8 - Jatapú River (2.017940° S, 58.203228° W); 9 - Flona Saracá-Taquera e Rebio Trombetas, Trombetas River (1.48163888889° S, 56.4573333333° W); 10 - Jari River valley (0.7000000000° S, 52.6666666667° W).
	Figure 2. Karyotypes of Proechimys goeldii (2n = 16): (a) conventional staining, (b) C-banding, (c) NOR. Karyotypes of Proechimys echinothrix (2n=32): (d) conventional staining, (e) C-banding, (f) NOR. Karyotypes of Proechimys cuvieri (2n=28): (g) conventional staining, (h) C-banding, (i) NOR. Bars = 10 μm.
	Figure 3. Telomeric marks in Proechimys cuvieri (a) from localities 7, 8 and 9; (b) P. cuvieri from locality 1; (c) P. gardneri from localities 5 and 6; (d) P. goeldii from locality 4; (e) P. guyannensis from localities 2 and 10; (f) P. guyannensis from locality 9; (g) P. echinothrix from localities 3 and 4; (h) P. longicaudatus from locality 6. Bar = 10 μm.
	Figure 4. 18S DNA labeling (indicated by arrows) (a) in Proechimys cuvieri from localities 7, 8 and 9; (b) P. cuvieri from locality 1; (c) P. gardneri from localities 5 and 6; (d) P. goeldii from locality 4; (e) P. guyannensis from localities 2 and 10; (f) P. guyannensis from locality 9; (g) P. echinothrix from localities 3 and 4; (h) P. longicaudatus from locality 6. Bar = 10 μm.
	Figure 5. Geographic distribution (dark area) of the 2n = 46 P. guyannensis cytotype, showing the collecting localities: 1 – Saracá-Taquera National Forest and Trombetas Biological Reserve, in Pará state (present study); 2 – São João da Baliza, Amapá (Bonvicino et al., 2005); 3 – Balbina hydroelectric reservoir, on the Uatumã River, in Amazonas state (Silva et al., 2012).
	Figure 6. Geographic distribution of the known P. cuvieri cytotypes. Dark area: 1 - Vale do rio Jari, in Pará state (Eler et al., 2012); 2 - Saracá-Taquera National Forest and Trombetas Biological Reserve, Pará (present study); 3 - lower Jatapú River, Amazonas (present study); 4 - Balbina hydroelectric reservoir, Uatumã River, Amazonas (Maia and Langguth, 1993; Silva et al., 2012); 5 - Rio Negro State Park, southern sector, Cueiras River, Amazonas (Silva et al., 2012), 6 - Jaú National Park, Amazonas (Patton et al., 2000); Area with vertical hatching (new cytotype): 7- upper Japurá River (present study); Area with cross hatching: 8, 9 and 10 - lower-mid, upper-mid, and headwaters of the Juruá River respectively (Patton et al., 2000); Area with horizontal hatching: 11 - Altamira, Xingu River, Pará (Patton et al., 2000), 12 - La Trinité Mountains, French Guiana (Reig et al., 1979).
	Figure 7. Geographic distribution of P. echinothrix. Dark area: known distribution of the species, extended to the region of the Jaú National Park (3) (Patton et al., 2000). Hatched area: proposed extension to the Canutama Extractivist Reserve (2) and the lower Jacinto River (3).

References [+] :

Amaral, Proechimys (Rodentia, Echimyidae): characterization and taxonomic considerations of a form with a very low diploid number and a multiple sex chromosome system. 2013, Pubmed