Karyotype differentiation in tellin shells (Bivalvia: Tellinidae)

Area of Science:

• Marine Biology
• Genetics
• Bivalve Taxonomy

Background:

• The taxonomy of Tellinidae, a large and diverse bivalve family, is complex due to shell morphology variations and limited molecular data.
• Previous studies have been hampered by morphological diversity, homoplasy in shell features, and a scarcity of molecular phylogenetic research.

Purpose of the Study:

• To perform a molecular cytogenetic analysis on four species of tellin shells: Bosemprella incarnata, Macomangulus tenuis, Moerella donacina, and Serratina serrata.
• To characterize these species molecularly using mitochondrial cytochrome c oxidase subunit I (COI) gene sequencing.
• To investigate chromosome structure and the distribution of specific gene clusters using fluorescent in situ hybridization (FISH).

Main Methods:

• Molecular cytogenetic analysis including karyotyping.
• Sequencing of the mitochondrial cytochrome c oxidase subunit I (COI) gene fragment.
• Fluorescent in situ hybridization (FISH) for mapping 45S and 5S rDNA, H3 histone gene clusters, and telomeric sequences.

Main Results:

• Karyotypes of the four tellin shell species exhibited variations in bi-armed and telocentric chromosomes.
• FISH analysis revealed distinct chromosomal distributions of 45S rDNA, 5S rDNA, and H3 histone gene clusters among the species.
• Vertebrate-type telomeric sequences were consistently found at the ends of all chromosomes in the analyzed species.

Conclusions:

• Fluorescent in situ hybridization (FISH) signals offer valuable data for understanding chromosome evolution within the Tellinidae family.
• FISH serves as an effective tool for identifying tellin shell specimens, aiding in molecular phylogenetic studies.
• This study highlights the utility of molecular cytogenetics in resolving taxonomic uncertainties in bivalves.