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Chromosome Diversity and Evolution in Helicoide a (Gastropoda: Stylommatophora): A Synthesis from Original and Literature Data

Authors :
Agnese Petraccioli
Paolo Crovato
Fabio Maria Guarino
Marcello Mezzasalma
Gaetano Odierna
Orfeo Picariello
Nicola Maio
Source :
Animals, Vol 11, Iss 9, p 2551 (2021)
Publication Year :
2021
Publisher :
MDPI AG, 2021.

Abstract

We performed a molecular and a comparative cytogenetic analysis on different Helicoidea species and a review of all the available chromosome data on the superfamily to provide an updated assessment of its karyological diversity. Standard karyotyping, banding techniques, and Fluorescence in situ hybridization of Nucleolus Organizer Region loci (NOR-FISH) were performed on fifteen species of three families: two Geomitridae, four Hygromiidae and nine Helicidae. The karyotypes of the studied species varied from 2n = 44 to 2n = 60, highlighting a high karyological diversity. NORs were on a single chromosome pair in Cernuella virgata and on multiple pairs in four Helicidae, representing ancestral and derived conditions, respectively. Heterochromatic C-bands were found on pericentromeric regions of few chromosomes, being Q- and 4′,6-diamidino-2-phenylindole (DAPI) negative. NOR-associated heterochromatin was C-banding and chromomycin A3 (CMA3) positive. Considering the available karyological evidence on Helicoidea and superimposing the chromosome data gathered from different sources on available phylogenetic inferences, we describe a karyotype of 2n = 60 with all biarmed elements as the ancestral state in the superfamily. From this condition, an accumulation of chromosome translocations led to karyotypes with a lower chromosome number (2n = 50–44). This process occurred independently in different lineages, while an augment of the chromosome number was detectable in Polygyridae. Chromosome inversions were also relevant chromosome rearrangements in Helicoidea, leading to the formation of telocentric elements in karyotypes with a relatively low chromosome count.

Details

Language :
English
ISSN :
20762615
Volume :
11
Issue :
9
Database :
Directory of Open Access Journals
Journal :
Animals
Publication Type :
Academic Journal
Accession number :
edsdoj.562cd3fe239d4404ac69d6759a0b44b3
Document Type :
article
Full Text :
https://doi.org/10.3390/ani11092551