Testing for age- and sex- specific mitonuclear epistasis in Drosophila
Data files
May 22, 2025 version files 151.73 KB
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dryad_data.zip
147.74 KB
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README.md
3.99 KB
Abstract
The need for efficient ATP production is predicted to result in the evolution of cooperation between the mitochondrial and nuclear encoded components of the electron transport system. Novel (i.e., mismatched) mitonuclear genotype combinations are therefore predicted to result in negative fitness consequences, which may become more prevalent with ageing. Such negative fitness effects are expected to be prominent in males, since maternal inheritance of mitochondria is predicted to lead to accumulation of male-harming mutations (the mother’s curse hypothesis). To test these predictions, we measured female and male fertility traits using a genetically diverse panel of 27 mitonuclear populations of Drosophila melanogaster with matched or experimentally mismatched mitonuclear genomes at different ages. We found no overall effect of mitonuclear mismatch. In females, we found no effect of mitonuclear epistasis. In males, we found limited evidence of mitonuclear epistasis affecting fitness in old age, however, not in the direction predicted. Experimentally mismatched males sired more offspring in one comparison. Sex-specific advantages of mismatched males might arise if novel nuclear alleles compensate for deleterious mitochondrial alleles that have accumulated. If such compensatory effects of novel mitonuclear combinations increasing fitness occur in nature, they could represent a possible counterforce to the mother’s curse.
Dataset DOI: 10.5061/dryad.dv41ns27n
Description of the data and file structure
Files and variables
File: dryad_data.zip
Description: File list - 7 .csv files, each labelled with the relevant data:
File descriptions
All files include variables:
- mito: mitochondrial genotype levels (A/B/C)
- nuclear: nuclear genotype levels (A/B/C)
- mtn (or similar): combined mitonuclear genotype levels (AA/AB/AC/etc.)
- coevolved: levels (matched/mismatched)
- mito_snp: the mitochondrial haplotypes levels 1 to 9
- LINE: mitonuclear population ID for the 27 mitolines levels (AA1/AA2/AA3/etc.)
- age: Male data includes "age" with levels (young/old) indicating male age (young = 5 days, old = 6 weeks)
Missing values are either blank cells or "NA"
body_data.csv
Body size data. Wing length and landmark area for female and male flies.
- FlyID: Individual fly identifier
- sex: female = f; male = m
- fam: unique identified for each vial in which flies laid by one female emerged
- Area: wing area (mm2)
- scaled_area: z-transformed wing area
female_fertility.csv
Data on fecundity for mitoline females.
- ID: unique female ID
- vial: oviposition vial for each female (1 to 7)
- progeny: counts of adult progeny emerging from each vial
- OLRE: observation level random effect
male_fertility.csv
Data on fecundity and hatching success for females mated with mitoline males.
- total_eggs: counts of eggs laid by tester female
- total_offs: counts of emerging larvae from total eggs
- total_fail: counts of unhatched eggs (total eggs - total offs)
- fertilised: calculated proportion of eggs that hatched
- OLRE: observation level random effect
sperm_defence.csv
Data for P1
- ID: unique male identifier
- Block: experimental block
- Day: day of remating
- cop.dur: copulation duration (mins)
- BW: counts of brown eyed offspring, i.e., competitor male sire
- RED: counts of red eyed offspring, i.e., focal male sire
- P1: calculated proportion of offspring from the first (focal) male
sperm_met_wrangled.csv
Data on sperm metabolic rate
- maleid: unique male identifier
- a1: relative abundance of autofluorescence decay for free NAD(P)H molecules (t1)
- a2: relative abundance of autofluorescence decay for protein-bound NAD(P)H molecules (t2)
- p.a2: a2/100
sperm_offence.csv
Data for P2
- ID: unique male identifier
- Block: experimental block
- Day: day of remating
- cop.dur: copulation duration (mins)
- BW: counts of brown eyed offspring, i.e., competitor male sire
- RED: counts of red eyed offspring, i.e., focal male sire
- P2: calculated proportion of offspring from the second (focal) male
sperm_viability_wrangled.csv
Data on sperm viability after live/dead staining in treatment or control
- male_ID: unique male identifier
- days: dissection day
- treatment: control (c) or treatment (t) after sperm exposure to control or stress medium before measurement
- live: counts of live sperm
- dead: counts of dead sperm
- block: experimental block
- total sperm: counts of total number of sperm
- viability: calculated proportion of life sperm
- OLRE: observation level random effect
Code/software
All code is available on GitHub: https://martingarlovsky.github.io/mito_age_fert/ and https://github.com/suvoigt/mitonuclear_snp_analysis/.
Access information
Other publicly accessible locations of the data:
- Mitochondrial and nuclear sequencing data can be retrieved from NCBI using SRA accessions PRJNA532313 and PRJNA853138, respectively.