Speciation by hybridization is emerging as a significant contributor to biological diversification. Yet, little is known about the relative contributions of (i) evolutionary novelty and (ii) sorting of preexisting parental incompatibilities to the build-up of reproductive isolation under this mode of speciation. Few studies have addressed empirically whether hybrid animal taxa are intrinsically isolated from their parents, and no study has so far investigated by which of the two aforementioned routes intrinsic barriers evolve. Here, we show that sorting of preexisting parental incompatibilities contributes to intrinsic isolation of a hybrid animal taxon. Using a genomic cline framework, we demonstrate that the sex-linked and mito-nuclear incompatibilities isolating the homoploid hybrid Italian sparrow at its two geographically separated hybrid-parent boundaries represent a subset of those contributing to reproductive isolation between its parent species, house and Spanish sparrows. Should such a sorting mechanism prove to be pervasive, the circumstances promoting homoploid hybrid speciation may be broader than currently thought, and indeed there may be many cryptic hybrid taxa separated from their parent species by sorted, inherited incompatibilities.
structure_input_file
'structure_input.txt': input file used when running structure. numbers in second column refer to:
1: house sparrows from Oslo, Norway
2: house sparrows from Hradec Králové, Czech Republic
3: house sparrows from sympatric population near Badajoz, Spain
4: Spanish sparrows from sympatric population near Badajoz, Spain
5: Spanish sparrows from the Gargano Peninsula
6: Spanish sparrows from Sardinia
7: F1-hybrids from aviary
structure_input.txt
Genotypes for house sparrow reference population
Genotypes for the individuals in the house sparrow reference population for the 77 SNP markers.
genotypes_house.xlsx
Genotypes for Spanish sparrow reference population
Genotypes for the individuals in the spanish sparrow reference population for the 77 SNP markers
genotypes_spanish.xlsx
Genotypes for parental sympatry test population
Genotypes for the individuals in the admixed test population. 'BGC column' refers to the number given to indivudlas by the bgc output.
genotypes_spain.xlsx
Genotypes for the hybrid-parents test population
Genotypes for the individuals in the hybrid-parents test population. 'BGC column' refers to the number given to individuals by the bgc output.
genotypes_italy.xlsx
File to link locus names with bgc output
File showing which loci refers to which 'bgc output number' for all 77 markers, only autosomal markers and only Z-linked markers
loci.xlsx
File with the code used when running bgc
File with the code used when running bgc
bgc_code.txt
bgc input file for house sparrow parental population (reference population), all 77 markers
bgc input file for house sparrow parental population (reference population)
house.txt
bgc input file for Spanish sparrow parental population (reference population), all 77 markers
bgc input file for Spanish sparrow parental population (reference population)
spanish.txt
bgc input file for hybrid-parent test population, all 77 markers
bgc input file for hybrid-parent test population, all 77 markers
admixed_spain.txt
a.out_parental sympatry
Output from BGC run on parental sympatry test population: estimates of cline parameter alpha for the 77 loci.
a.out_spain.txt
b.out_parental sympatry
Output from BGC run on parental sympatry test population: estimates of cline parameter beta for the 77 loci.
b.out_spain.txt
hi.out_parental sympatry
Output from BGC run on parental sympatry test population: estimates of hybrid index.
hi.out_spain.txt
qa.out_parental sympatry
Output from BGC run on parental sympatry test population: estimates of alpha parameter quantiles for the 77 loci.
qa.out_spain.txt
qb.out_parental sympatry
output from BGC run on parental sympatry test population: estimates of beta parameter quantiles for the 77 loci
qb.out_spain.txt
bgc input file for house sparrow parental population (reference population) when analysing autosomal loci separately
input file for house sparrow parental population (reference population) when analysing autosomal loci separately in parental sympatry
house_autosomal.txt
bgc input file for Spanish sparrow parental population (reference population) when analysing autosomal loci separately in parental sympatry
bgc input file for Spanish sparrow parental population (reference population) when analysing autosomal loci separately in parental sympatry
spanish_autosomal.txt
bgc input file for parental sympatry test population when analysing autosomal loci separately
bgc input file for parental sympatry test population when analysing autosomal loci separately
admixed_spain_autosomal.txt
b.out_autosomal_parental sympatry
output from BGC run on parental sympatry test population: estimates of cline parameter beta for the 55 autosomal loci analyzed separately
b.out_spain_autosomal.txt
bgc input file for house sparrow parental population (reference population) when analysing Z-linked loci separately in parental sympatry
bgc input file for house sparrow parental population (reference population) when analysing Z-linked loci separately in parental sympatry
house_Z.txt
bgc input file for Spanish sparrow parental population (reference population) when analysing Z-linked loci separately in parental sympatry
bgc input file for Spanish sparrow parental population (reference population) when analysing Z-linked loci separately i parental sympatry
spanish_Z.txt
bgc input file for test population when analysing Z-linked loci separately in parental sympatry
bgc input file for test population when analysing Z-linked loci separately in parental sympatry
admixed_spain_Z.txt
b.out_Z_parental sympatry
output from BGC: estimates of cline parameter beta for the 21 Z-linked loci analyzed separately in parental sympatry
b.out_spain_Z.txt
bgc input file for hybrid-parents test population (all 77 loci)
bgc input file for hybrid-parents test population (all 77 loci)
admixed_italy.txt
a.out_hybrid-parents analysis
output from BGC: estimates of cline parameter alpha for 77 the loci used in the hybrid-parents analysis
a.out_italy.txt
b.out_hybrid-parents analysis
output from BGC: estimates of cline parameter beta for 77 the loci used in the hybrid-parents analysis
b.out_italy.txt
hi.out_hybrid-parents analysis
output from BGC: estimates of hybrid index for the individuals in the hybrid-parents test population
hi.out_italy.txt
qa.out_hybrid-parents analysis
bgc output from hybrid-parents analysis: estimates of alpha parameter quantiles for the 77 loci
qa.out_italy.txt
qb.out_hybrid-parents analysis
bgc output from hybrid-parents analysis: estimates of beta parameter quantiles for the 77 loci
qb.out_italy.txt