Chromosomes of Lepidochitona caprearum (Scacchi, 1836) (Polyplacophora, Acanthochitonina, Tonicellidae) provide insights into Acanthochitonina karyological evolution

By

Petraccioli, Agnese
Maio, Nicola
Odierna, Gaetano

Type

Article

Date of Publication

2012

Original Publication

Comparative cytogenetics : international journal of plant & animal cytogenetics, karyosystematics and molecular systematics

Volume

6

Series / Issue

Issue: 4

Pages

397-407

Subjects

Acanthochitonina , Chitons , chromosome banding , chromosome evolution , heterochromatin , Lepidochitona caprearum

Contributed by

Pensoft Publishers

Language

English

Published by

St. Petersburg, Russia [Published] with technical support of Zoological Institute RAS [2007]-

Identifiers

DOI: https://doi.org/10.3897/compcytogen.v6i4.3722

 

Abstract

We describe the karyotype, location of nucleolus-organizing regions (NORs) and heterochromatin composition and distribution in Lepidochitona caprearum (Scacchi, 1836). The examined specimens had 2n=24 chromosomes; the elements of pairs 1 – 4 were metacentric, subtelocentric those of the fifth pair, telocentric the elements of other pairs. NOR-FISH, AG-NOR- and CMA3 banding showed NORs localized on pericentromeric regions of a medium small sized, telocentric chromosome pair. After C-banding or digestions with restriction enzyme NOR associate heterochromatin only was cytologically evident, resulting CMA3 positive. The comparison with other chitons chromosome data, other than to evidence a karyotypic similarity of L. caprearum to species of suborder Acanthochitonina, allows also to infer that chromosome evolution in the suborder mainly occurred via reduction of the number of the chromosomes by centric fusions, which took place repeatedly and independently in the different lineages of Acanthochitonina.