Article
Karyotypical Confirmation of Natural Hybridization between Two Manatee Species, Trichechus manatus and Trichechus inunguis
Registro en:
OLIVEIRA, Edivaldo H. C. de et al. Karyotypical Confirmation of Natural Hybridization between Two Manatee Species, Trichechus manatus and Trichechus inunguis. Life, v.12, 616, p. 1 - 12, Apr. 2022.
2169-1576
10.3390/ life12050616
Autor
Oliveira, Edivaldo H. C. de
Gomes, Anderson J. B.
Costa, Alexandra F.
LIma, Renata Emin
Bonvicino, Cibele R.
Viana, Maria C.
Reis, Laura M. A.
Vidal, Marcelo D.
Cavalcanti, Mirella V. G.
Attademo, Fernanda L. N.
Luna, Fábia O.
Siciliano, Salvatore
Resumen
Two species of manatees are found in Northern Brazil—the Antillean manatee (Trichechus
manatus), which is found along the coast from Florida to Northeastern Brazil, and the Amazonian
manatee (Trichechus inunguis), endemic to the Amazon drainage basin. These species show a sympatric
distribution in the region of the Marajó Archipelago, an estuarine area surrounding the Amazon
River mouth. There is evidence of the occurrence of interspecific hybrids in this area, based on
mitochondrial DNA analyses, although the use of nuclear markers has not corroborated this proposal.
Considering that these species show very distinct karyotypes, despite being closely related (2n = 48 in
T. manatus and 2n = 56 in T. inunguis), hybrids would present distinct chromosome numbers. Based on
this, we conducted cytogenetic analyses using classic and molecular techniques in three calves found
stranded in the Marajó Island and Amapá coast. The results showed that one of them, morphologically
classified as T. inunguis, presented the correspondent karyotype, with 2n = 56. However, the other
two, which were phenotypically similar to T. manatus, showed 2n = 49. Despite the same diploid
number, their G-banding patterns revealed some differences. The results of the distribution of some
microsatellite sequences have also confirmed the heterozygosity of some chromosomal pairs in these
two individuals. These results are the first indubitable confirmation of the occurrence of natural
hybrids between T. manatus and T. inunguis, and also brings about some issues concerning the viability
of hybrids, considering that these two individuals do not correspond to an F1 hybrid, but instead,
both presented a possible F2 karyotype..