DOI: 10.5061/dryad.xsj3tx9tr
title: Data from: Introgression and parental conflict underlie repeated occurrences of postzygotic isolation

description: Postzygotic reproductive isolation is often thought to accumulate as a
 byproduct of neutral divergence. Yet, it frequently evolves rapidly, in
 line with non-neutral evolution. A major driver of intrinsic postzygotic
 reproductive barriers is intragenomic conflicts, such as conflict between
 maternal and paternal interests in resource allocation to offspring (i.e.,
 parental conflict). Parental conflict may underlie hybrid seed
 inviability, a common and rapidly evolving reproductive barrier in
 angiosperms. Yet, in closely related, hybridizing species, it remains
 unclear how intragenomic conflicts and introgression interact to determine
 the fate of incompatibility alleles in nature. Here, we explore repeated
 incidences of hybrid seed inviability in a rising model: the Mimulus
 guttatus species complex. Using an extensive, range-wide crossing survey,
 we discover patterns of hybrid seed inviability within the widespread M.
 guttatus that are better described by geography than phylogeny. These
 patterns of reproductive isolation transgress species boundaries, as
 geographically-proximate but phylogenetically-distant species also exhibit
 similar patterns of hybrid seed inviability with allopatric populations of
 M. guttatus. We find strong support that patterns of reproductive
 isolation are consistent with parental conflict. Lastly, we provide
 evidence that introgression may underlie shared patterns of hybrid seed
 inviability between two species within this complex. Such introgression
 could have led to cascading reproductive isolation with other closely
 related species, creating a complex landscape of incompatibility. Overall,
 this work suggests that parental conflict and introgression can interact
 to shape the rapid and repeated evolution of strong reproductive isolation
 in the wild.
description: # Data from: Introgression and parental conflict underlie repeated
 occurrences of postzygotic isolation ## Summary of Experiment This data
 repository contains data from three experiments. A summary of those
 experiments is below; additional details can be found in the associated
 manuscript. 1. **Crossing surveys:** To assess hybrid seed inviability
 within the widespread *M. guttatus*, we grew 3-5 individuals from 1 inbred
 line/maternal family for each of 23 populations of *M. guttatus*. Upon
 flowering, we crossed all accessions to each other in a nearly full
 diallel design, totaling 426 unique cross directions (out of a possible
 506), with a mean of 4 replicate crosses per combination (range: 1-12,
 totaling 1,742 crosses). Based on the results of these crosses, we
 performed follow-up crossing surveys that incorporated other species
 within the complex: *Mimulus decorus*, *M. corallinus*, and *M.
 glaucescens*. Data from these crosses includes: Visual assessment of seed
 viability based on morphology (shriveled/flat corresponding to inviable,
 or round corresponding to viable); Germination rates on 0.6% agar media
 for 30 seeds per cross; Measurements of seed width. 2. **Embryo
 Rescue:** To determine if observed hybrid seed inviability was caused by
 defects in the endosperm rather than the embryo itself, we performed an
 embryo rescue experiment. Early developing seeds were grown on Murashige
 and Skoog media supplemented with 4 % sucrose to functionally compensate
 for the endosperm by providing external nutrition needed for growth. Seeds
 were scored for germination weekly for four weeks. 3. **Complementation
 test:** In order to assess whether the genetic basis of hybrid seed
 inviability with Northern *Mimulus gutattus* is shared between Southern
 *M. decorus* and *M. corallinus*, we performed a complementation test. We
 first crossed these two species reciprocally, then self-fertilized one
 reciprocal F1 from each cross direction to create reciprocal F2
 populations. We planted 5 replicates of each parent, along with 15 F1s
 from each cross direction, and roughly 100 F2s from each cross direction.
 We performed an average of 3 replicate crosses per plant (range: 1-10),
 totaling 761 crosses and assessed the percentage of viable seed per fruit.
 ## File Structure ### 1\) Crossing survey data ### File: heat_map_data.csv
 This file contains the results of visual viability assessment from the
 *Mimulus guttatus* range-wide crossing survey. The data table has 12
 columns: * female.pop: Line number of dam * female.rep: Replicate number
 of dam * female.type: Lineage identity of dam * male.pop: Line number of
 sire * male.rep: Replicate number of sire * male.type: Lineage identity of
 sire * total.seed: Number of seeds produced by cross * number.inviable:
 Number of seeds assessed as inviable * number.viable: Number of seeds
 assessed as inviable * proportion.viable: number.viable divided by
 total.seed * cross.type: lineage identity of each parent, with dam listed
 first * counter: Initials of data collector * notes: Notes on seed
 phenotypes ### File: corallinusXdecorus_crosses.xlsx This file contains
 the results of visual viability assessment from additional crosses
 completed using other members of the species complex.\ The data table has
 12 columns: * female.pop: Line name of dam * female.rep: Replicate number
 of dam * female.type: Lineage identity of dam * male.pop: Line name of
 sire * male.rep: Replicate number of sire * male.type: Lineage identity of
 sire * total.seed: Number of seeds produced by cross * number.inviable:
 Number of seeds assessed as inviable * number.viable: Number of seeds
 assessed as inviable * proportion.viable: number.viable divided by
 total.seed * cross.type: lineage identity of each parent, with dam listed
 first * counter: Initials of data collector * notes: Notes on seed
 phenotypes ### File: seed_sizes.txt This file contains measurements of
 seed size. The data table has 13 columns: * Mat: Line name of dam *
 Mat.rep: Replicate number of dam * Pat: Line name of sire * Pat.rep:
 Replicate number of sire * cross.designation: Grouping of the crosses *
 Mat.type: Lineage identity of dam * Pat.type: Lineage identity of sire *
 Mat.type.2: Lineage identity of dam, with *M. glaucescens* combined into
 the "Sierra" lineage * Pat.type.2: Lineage identity of sire,
 with *M. glaucescens* combined into the "Sierra" lineage *
 cross.specific: Lineage identity of each parent, with dam listed first *
 cross: Lineage identity of each parent, with dam listed first * image:
 Image number seed measurement was taken from * seed.width: Seed width
 measured in mm ### 2\) Embryo Rescue ### File: embryo_rescue.xlsx This
 file contains the results of the embryo rescue experiment. The data table
 has four columns: * line_ID: Names of the lines crossed, dam listed first
 * cross: Lineage identity of lines crossed, dam listed first *
 germ.percent: Percentage of seeds that germinated * index: Whether the
 cross was part of the control ("Germination assay") or embryo
 rescue ("8 DAP") ### 3\) Complementation Test ### File:
 corallinusxSDec_Complementation_Test_seedcount.txt This file contains
 results of visual viability assessment from complementation test crosses.
 The data table has 12 columns: * Plant: Line name of focal plant * Rep:
 Replicate number of focal plant * unique_ID: Line name and replicate
 number combined * generation: Generation of focal plant (F1, F2, or parent
 line) * ID: Cross ID * inviable_seed_count: Number of inviable seeds *
 viable_seed_count: Number of viable seeds * total_seeds: Total number of
 seeds * prop_viable: viable_seed_count divided by total_seeds ##
 Population codes used across tables * *Mimulus corallinus* = COR *
 Northern *Mimulus guttatus* = NORTH = NGUT * Southern *Mimulus decorus* =
 SDEC * Northern *Mimulus decorus* = NDEC * Sierra *Mimulus guttatus* =
 SIERRA * Coastal *Mimulus guttatus* = COAST * *Mimulus glaucescens* =
 GLAUC Note: blank cells indicate 'not applicable'