A very short, functionally constrained sequence diagnoses cone snails in several Conasprella clades

Area of Science:

• Marine Biology
• Genetics
• Taxonomy

Background:

• Traditional classification places ~700 cone snail species in the genus Conus.
• Emerging evidence suggests a distinct clade, Conasprella, warrants separate classification.
• Previous studies utilized conserved intronic sequences for phylogenetic analysis.

Purpose of the Study:

• To resolve problematic phylogenetic relationships within the conasprellan clade.
• To distinguish Conasprella from the genus Conus using molecular data.
• To investigate potential functional changes in gene expression post-divergence.

Main Methods:

• Analysis of a conserved intronic sequence (intron 9) of the γ-glutamyl carboxylase gene.
• Sequencing of a 338 bp region of intron 9.
• Identification of synapomorphic mutations and conserved regions for phylogenetic comparison.

Main Results:

• Intron 9 sequences effectively resolved deep phylogenetic relationships within Conasprella.
• Synapomorphic mutations at 39 sites clearly delineated subgroups within Conasprella.
• Conserved regions of intron 9 were non-alignable between Conus and Conasprella, indicating distinct homology.

Conclusions:

• The γ-glutamyl carboxylase gene's intron 9 provides a robust marker for distinguishing Conus and Conasprella.
• Molecular data supports the phylogenetic separation of Conasprella from Conus.
• Divergence may be associated with significant functional changes in γ-glutamyl carboxylase gene expression.