Story perspectives

Island Spider's Small Genome Surprises with High Diversity

10/15/2025

40 7

Summary

Story summary

Dysdera tilosensis, a spider endemic to the Canary Islands, has a genome of 1.7 billion base pairs, about half of its mainland relative Dysdera catalonica's 3.3 billion.
Despite the smaller genome, Dysdera tilosensis shows greater genetic diversity.
The study attributes downsizing to sustained selective pressures in stable island populations, challenging the view that island species typically have larger genomes.
The findings were published in Molecular Biology and Evolution.

1 of 1

Story summary

Dysdera tilosensis, a spider endemic to the Canary Islands, has a genome of 1.7 billion base pairs, about half of its mainland relative Dysdera catalonica's 3.3 billion.
Despite the smaller genome, Dysdera tilosensis shows greater genetic diversity.
The study attributes downsizing to sustained selective pressures in stable island populations, challenging the view that island species typically have larger genomes.
The findings were published in Molecular Biology and Evolution.