| Autor: |
Tyler K. Chafin, Binod Regmi, Marlis R. Douglas, David R. Edds, Karma Wangchuk, Sonam Dorji, Pema Norbu, Sangay Norbu, Changlu Changlu, Gopal Prasad Khanal, Singye Tshering, Michael E. Douglas |
| Jazyk: |
angličtina |
| Rok vydání: |
2021 |
| Předmět: |
|
| Zdroj: |
Royal Society Open Science, Vol 8, Iss 10 (2021) |
| Druh dokumentu: |
article |
| ISSN: |
2054-5703 |
| DOI: |
10.1098/rsos.210727 |
| Popis: |
The recurrence of similar evolutionary patterns within different habitats often reflects parallel selective pressures acting upon either standing or independently occurring genetic variation to produce a convergence of phenotypes. This interpretation (i.e. parallel divergences within adjacent streams) has been hypothesized for drainage-specific morphological ‘ecotypes’ observed in polyploid snowtrout (Cyprinidae: Schizothorax). However, parallel patterns of differential introgression during secondary contact are a viable alternative hypothesis. Here, we used ddRADseq (N = 35 319 de novo and N = 10 884 transcriptome-aligned SNPs), as derived from Nepali/Bhutanese samples (N = 48 each), to test these competing hypotheses. We first employed genome-wide allelic depths to derive appropriate ploidy models, then a Bayesian approach to yield genotypes statistically consistent under the inferred expectations. Elevational ‘ecotypes’ were consistent in geometric morphometric space, but with phylogenetic relationships at the drainage level, sustaining a hypothesis of independent emergence. However, partitioned analyses of phylogeny and admixture identified subsets of loci under selection that retained genealogical concordance with morphology, suggesting instead that apparent patterns of morphological/phylogenetic discordance are driven by widespread genomic homogenization. Here, admixture occurring in secondary contact effectively ‘masks’ previous isolation. Our results underscore two salient factors: (i) morphological adaptations are retained despite hybridization and (ii) the degree of admixture varies across tributaries, presumably concomitant with underlying environmental or anthropogenic factors. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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