Análises cromossômica e molecular de Pterygoplichthys Pardalis (Castelneau, 1855) (Siluriformes: loricariidae): uma espécie nativa da Bacia Amazônica e invasora em outros países
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2021-07-06Autor
http://lattes.cnpq.br/4609858881694961
https://orcid.org/0000-0002-8985-9000
GUIMARÃES, Alcimara dos Santos
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Pterygoplichthys pardalis is one of the 15 species that make up the genus
Pterygoplichthys Family Loricariidae, Order Siluriformes. This group of fish is
native to South America, but there is a record of introduction in five continents
and exotic populations of P. pardalis have settled in 16 countries. Despite its
commercial and socioenvironmental importance, P. pardalis is still poorly studied
from a genetic perspective. In this work, we describe for the first time the
karyotype of P. pardalis and compare individuals from native and exotic
populations through the mitochondrial gene Cytochrome oxidase I. Ten
individuals collected in Lake Pacoval and Lake Arapixuna, on the right bank of
the Amazon River, were analyzed. The karyotype showed diploid number 2n=52
and NF=100 with no morphological variation between males and females. The
location of the nucleolus organizer regions and the 18S ribosomal marker were
coincident in pair 14, while the 5S site was detected in the interstitial position of
pair 13. The constitutive heterochromatin is restricted and located in the telomeric
region of only four pairs, of which three recorded positive CMA3 signals at the
same location. Telomeric markings were observed only at the ends of
chromosomes. The species P. pardalis diverged from other congeners due to
variation in the karyotype formula. The molecular variation of the Cytochrome
oxidase I gene revealed five mutations that differentiate four haplotypes.
Haplotype 1 is the most frequent and shared by individuals from native and exotic
populations. The exotic population of the Philippines is the most diverse and may
represent the original introduction event of P. pardalis into Southeast Asia.