The Z chromosome is enriched for sperm proteins in two divergent species of Lepidoptera

Andrew J. Mongue, James R. Walters, Mark Ungerer
2018 Genome  
12 Genes that promote sexual conflict, such as those with a sex-limited fitness benefit, are expected to 13 accumulate differentially on sex chromosomes relative to autosomes. Few tests of this hypothesis exist 14 for male homogametic (ZZ) taxa, however, and most use RNA expression data to identify such genes. 15 Here, we employ a different identification method by using proteomic analysis of sperm cells to identify 16 genes with a sex-limited benefit. We tested for a bias in genomic location
more » ... genomic location of sperm protein genes in two 17 species of Lepidoptera. An excess of sperm protein genes was identified on the Z chromosomes of both 18 the Carolina sphinx moth (Manduca sexta) and the monarch butterfly (Danaus plexippus). Taking into 19 consideration a Z-autosome fusion in monarchs, we discover that the ancestrally sex-linked portion of 20 the genome is the source of this enrichment while the newly sex-linked portion still appears similar to 21 autosomes in relative abundance of sperm protein genes. Together, these results point to an 22 enrichment of male-beneficial genes on the Z chromosome and demonstrate the usefulness of 23 proteomic datasets in sexual conflict research. 24 25 26 Keywords 27 sex chromosomes, sexual antagonism, sexual conflict, sperm, female heterogamety, Lepidoptera 28 29
doi:10.1139/gen-2017-0068 pmid:28961403 fatcat:gruyzqsr7fhylbuiaz5a4whqmy