DOI: 10.5061/dryad.bh19kj8
title: Data from: Sperm competitive advantage of a rare mitochondrial haplogroup linked to differential expression of mitochondrial oxidative phosphorylation genes

description: Maternal inheritance of mitochondria creates a sex-specific selective
 sieve through which mitochondrial mutations harmful to males but not
 females accumulate and contribute to sexual differences in longevity and
 disease susceptibility. Because eggs and sperm are under disruptive
 selection, sperm are predicted to be particularly vulnerable to the
 genetic load generated by maternal inheritance, yet evidence for
 mitochondrial involvement in male fertility is limited and controversial.
 Here, we exploit the coexistence of two divergent mitochondrial
 haplogroups (A and B2) in a Neotropical arachnid to investigate the role
 of mitochondria in sperm competition. DNA profiling demonstrated that
 B2-carrying males sired more than three times as many offspring in sperm
 competition experiments than A males, and this B2 competitive advantage
 cannot be explained by female mitochondrial haplogroup or male nuclear
 genetic background. RNA-Seq of testicular tissues implicates differential
 expression of mitochondrial oxidative phosphorylation (OXPHOS) genes in
 the B2 competitive advantage, including a 22-fold upregulation of atp8 in
 B2 males. Previous comparative genomic analyses have revealed functionally
 significant amino acid substitutions in differentially expressed genes,
 indicating that the mitochondrial haplogroups differ not only in
 expression but also in DNA sequence and protein functioning. However,
 mitochondrial haplogroup had no effect on sperm number or sperm viability,
 and, when females were mated to a single male, neither male haplogroup,
 female haplogroup nor the interaction between male/female haplogroup
 significantly affected female reproductive success. Our findings therefore
 suggest that mitochondrial effects on male reproduction may often go
 undetected in noncompetitive contexts and may prove more important in
 nature than is currently appreciated.
description: A-Haplogroup
 Mitochondrial Reference Genome Cordylochernes
 scorpioidesAn annotated reference
 genome for the Cordylochernes scorpioides A mitochondrial haplogroup in
 NCBI xml format1.1
 mtGenome-A-Haplo.xmlB2-Haplogroup
 Mitochondrial Reference Genome Cordylochernes
 scorpioidesAn annotated reference
 genome for the Cordylochernes scorpioides B2 mitochondrial haplogroup in
 NCBI xml format1.2
 mtGenome-B2-Haplo.xmlMitochondrial DNA
 Expression in C. scorpioides Testicular TissueThis file provides the
 OXPHOS and rRNA gene expression data in counts per million for the five A
 Haplogroup and the five B2 Haplogroup replications.1.3 mtDNA
 Expression.xlsxqPCR Estimates of mtDNA
 Concentration in Testes of A and B2 Haplogroup MalesThis file provides
 estimates of the number of mitochondria per cell in the testes of A and B2
 Haplogroup males based on comparative quantitative PCR (qPCR). To estimate
 the number of mitochondria per cell, we amplified a conserved, 142-bp
 region of the atp6 gene. As an internal control, we amplified a 113-bp
 region of a single copy, X-chromosome-linked microsatellite
 locus.1.4
 qPCR mtDNA concentration.xlsxMolecular paternity
 assignment data to assess haplogroup effects on sperm competitive
 abilityMitochondrial haplogroup
 effects on sperm competitive ability were assessed in two-male sperm
 competition experiments in which initially virgin females were each mated
 to two males, one carrying A-haplogroup mitochondria and the other
 B2-haplogroup mitochondria. To complement a previous study in which
 competing A and B2 haplogroup males were mated exclusively to A-haplogroup
 females, only B2-haplogroup females were used in this study. Results from
 the current study were analyzed separately, and data from the two studies
 were also pooled to assess possible female haplogroup and male by female
 haplogroup effects on sperm competitive ability.1.5 Sperm competition
 data.xlsx