A ZZ/ZW sex chromosome system in Cheirodontinae fish

概要

論文の詳細を見る
Cytogenetic studies were carried out on two Neotropical fish species of the subfamily Cheirodontinae. Odontostilbe paranensis and Holoshestes heterodon, from Mogi-guacu River (Brazil), were characterized by 2n=52 chromosomes. Males of O. paranensis showed 18 meta-submetacentric, six subtelocentric and two acrocentric chromosome pairs, resulting in a fundamental number of 100. Females of this species presented a karyotype composed of 18 meta-submetacentric pairs, six subtelocentric pairs, one acrocentric pair and also one medium submetacentric chromosome and one medium acrocentric element. The karyotype of females of H. heterodon presented 18 meta-submetacentric, six subtelocentric and one acrocentric chromosome pairs, and two single small chromosomes - a metacentric one and an acrocentric element. A fundamental number of 101 was detected on females of both species. The present results suggest the occurrence of ZZ/ZW sex chromosomes on these two species, characterized by an acrocentric Z chromosome and by a morphologically variable W chromosome.