Meiotic drive impacts expression and evolution of x-linked genes in stalk-eyed flies.
Although sex chromosome meiotic drive has been observed in a variety of species for over 50 years, the genes causing drive are only known in a few cases, and none of these cases cause distorted sex-ratios in nature. In stalk-eyed flies (Teleopsis dalmanni), driving X chromosomes are commonly found at frequencies approaching 30% in the wild, but the genetic basis of drive has remained elusive due to reduced recombination between driving and non-driving X chromosomes. Here, we used RNAseq to identify transcripts that are differentially expressed between males carrying either a driving X (XSR) or a standard X chromosome (XST), and found hundreds of these, the majority of which are X-linked. Drive-associated transcripts show increased levels of sequence divergence (dN/dS) compared to a control set, and are predominantly expressed either in testes or in the gonads of both sexes. Finally, we confirmed that XSR and XST are highly divergent by estimating sequence differentiation between the RNAseq pools. We found that X-linked transcripts were often strongly differentiated (whereas most autosomal transcripts were not), supporting the presence of a relatively large region of recombination suppression on XSR presumably caused by one or more inversions. We have identified a group of genes that are good candidates for further study into the causes and consequences of sex-chromosome drive, and demonstrated that meiotic drive has had a profound effect on sequence evolution and gene expression of X-linked genes in this species.
Department of Biology, University of Maryland, College Park, Maryland, United States of America.
Josephine A
JA
Reinhardt
Department of Biology, University of Maryland, College Park, Maryland, United States of America; Department of Biology, University of Rochester, Rochester, New York, United States of America.
Cara L
CL
Brand
Department of Biology, University of Maryland, College Park, Maryland, United States of America.
Kimberly A
KA
Paczolt
Bard College, Annadale-on-Hudson, New York, United States of America.
Philip M
PM
Johns
Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York, United States of America.
Richard H
RH
Baker
Department of Biology, University of Maryland, College Park, Maryland, United States of America.
Gerald S
GS
Wilkinson
D000818:Animals; D005075:Biological Evolution; D004175:Diptera / Q000235:genetics; D005260:Female; D050172:Genes, X-Linked; D059014:High-Throughput Nucleotide Sequencing; D008297:Male; D008540:Meiosis / Q000235:genetics*; D012730:Sex Chromosomes / Q000235:genetics*; D012744:Sex Ratio; D014960:X Chromosome / Q000235:genetics*