DOI: 10.5061/dryad.n1k53
title: Data from: Chromosomal rearrangements directly cause underdominant F1 pollen sterility in Mimulus lewisii-M. cardinalis hybrids

description: Chromosomal rearrangements can contribute to the evolution of postzygotic
 reproductive isolation directly, by disrupting meiosis in F1 hybrids, or
 indirectly, by suppressing recombination among genic incompatibilities.
 Because direct effects of rearrangements on fertility imply fitness costs
 during their spread, understanding the mechanism of F1 hybrid sterility is
 integral to reconstructing the role(s) of rearrangements in speciation. In
 hybrids between monkeyflowers Mimulus cardinalis and M. lewisii,
 rearrangements contain all quantitative trait loci (QTLs) for both
 premating barriers and pollen sterility, suggesting that they may have
 facilitated speciation in this model system. We used artificial chromosome
 doubling and comparative mapping to test whether heterozygous
 rearrangements directly cause underdominant male sterility in M.
 lewisii-M. cardinalis hybrids. Consistent with a direct chromosomal basis
 for hybrid sterility, synthetic tetraploid F1s showed highly restored
 fertility (83.4% pollen fertility) relative to diploids F1s (36.0%).
 Additional mapping with M. parishii-M. cardinalis and M. parishii-M.
 lewisii hybrids demonstrated that underdominant male sterility is caused
 by one M. lewisii-specific and one M. cardinalis-specific reciprocal
 translocation, but that inversions had no direct effects on fertility. We
 discuss the importance of translocations as causes of reproductive
 isolation, and consider models for how underdominant rearrangements spread
 and fix despite intrinsic fitness costs.
description: Treatment conditions,
 flow cytometry data, and pollen counts for ploidy manipulation of M.
 lewisii x M. cardinalis F1 hybridsThis is a concatenated
 file of data from 2011 and 2012 experiments. Individuals (each with a
 unique ID) are organized by row. Columns indicate # fertile pollen grains
 counted, # sterile pollen, proportion fertile pollen, cross type (M.
 lewisii x M. cardinalis F1, or parental: LEW or CARD), # 2C (diploid)
 nuclei (from flow cytometry), # 4C (tetraploid) nuclei, proportion 2C,
 experiment year, treatment (colchicine or H2O), colchicine concentration,
 and treatment length.colch2011+2012.xlsxGenotypes and pollen fertility of M. parishii x M. cardinalis F2 mapping populationGenotypes of M. parishii x M. cardinalis F2s (individuals organized in rows) analyzed for linkage mapping and pollen fertility. Marker names (columns) are denoted with "e" prefix (e = MgSTS). Pollen fertility data are # fertile and # sterile grains counted. A = M. cardinalis homozygote, B = M. parishii homozygote, H = heterozygous.pcf2-geno+pollen.xlsxGenotypes and pollen fertility of M. parishii x M. lewisii F2 mapping populationGenotypes of M. parishii x M. lewisii F2s (individuals organized in rows) analyzed for linkage mapping and pollen fertility. Marker names (columns) are denoted with "e" prefix (e = MgSTS). Cross denotes whether the F2 was derived from a M. parishii x M. lewisii F1 (PL), or M. lewisii x M. parishii F1 (LP), maternal parent listed first. Pollen fertility data are # fertile and # sterile grains counted. A = M. lewisii homozygote, B = M. parishii homozygote, H = heterozygous.plf2-geno+pollen.xlsxPollen fertility for M. cardinalis, M. lewisii, and M. parishii parents and F1sPollen counts (# fertile, and # sterile) for M. cardinalis, M. lewisii, and M. parishii parents and F1s, used to compare pollen fertility distribution across genotypes. CARD = M. cardinalis, LEW = M. lewisii, PAR = M. parishii, PC = PARxCARD, PL = PARxLEW, LP = LEWxPAR, maternal parent listed first.parentF1fert.xlsx