Island-specific evolution of a sex-primed autosome in a sexual planarian.

ABSTRACT: The sexual strain of the planarian Schmidtea mediterranea, indigenous to Tunisia and several Mediterranean islands, is a hermaphrodite^1,2. Here we isolate individual chromosomes and use sequencing, Hi-C^3,4 and linkage mapping to assemble a chromosome-scale genome reference. The linkage map reveals an extremely low rate of recombination on chromosome 1. We confirm suppression of recombination on chromosome 1 by genotyping individual sperm cells and oocytes. We show that previously identified genomic regions that maintain heterozygosity even after prolonged inbreeding make up essentially all of chromosome 1. Genome sequencing of individuals isolated in the wild indicates that this phenomenon has evolved specifically in populations from Sardinia and Corsica. We find that

SUBMITTER: Guo L 

PROVIDER: S-EPMC9177419 | biostudies-literature | 2022 Jun

REPOSITORIES: biostudies-literature