hylogenomics, introgression, and demographic history of South American true toads (Rhinella

Author(s)

Rivera, Danielle ^{[1, 2]} ; Prates, Ivan ^{[3, 4]} ; Firneno, Jr., Thomas J. ^{[1, 2]} ; Rodrigues, Miguel Trefaut ^[5] ; Caldwell, Janalee P. ^{[6, 7]} ; Fujita, Matthew K. ^{[1, 2]}

Affiliation

^[1] Univ Texas Arlington, Dept Biol, Arlington, TX 76019 - USA

^[2] Univ Texas Arlington, Amphibian & Reptile Divers Res Ctr, Arlington, TX - USA

^[3] Univ Michigan, Museum Zool, Ann Arbor, MI 48109 - USA

^[4] Univ Michigan, Dept Ecol & Evolutionary Biol, Ann Arbor, MI - USA

^[5] Univ Sao Paulo, Inst Biociencias, Dept Zool, Sao Paulo, SP - Brazil

^[6] Univ Oklahoma, Sam Noble Museum, Norman, OK - USA

^[7] Univ Oklahoma, Dept Biol, Norman, OK - USA

• Document type: Journal article
• Source: Molecular Ecology; v. 31, n. 3 DEC 2021.
• Web of Science Citations: 0

Abstract

The effects of genetic introgression on species boundaries and how they affect species' integrity and persistence over evolutionary time have received increased attention. The increasing availability of genomic data has revealed contrasting patterns of gene flow across genomic regions, which impose challenges to inferences of evolutionary relationships and of patterns of genetic admixture across lineages. By characterizing patterns of variation across thousands of genomic loci in a widespread complex of true toads (Rhinella), we assess the true extent of genetic introgression across species thought to hybridize to extreme degrees based on natural history observations and multilocus analyses. Comprehensive geographic sampling of five large-ranged Neotropical taxa revealed multiple distinct evolutionary lineages that span large geographic areas and, at times, distinct biomes. The inferred major clades and genetic clusters largely correspond to currently recognized taxa; however, we also found evidence of cryptic diversity within taxa. While previous phylogenetic studies revealed extensive mitonuclear discordance, our genetic clustering analyses uncovered several admixed individuals within major genetic groups. Accordingly, historical demographic analyses supported that the evolutionary history of these toads involved cross-taxon gene flow both at ancient and recent times. Lastly, ABBA-BABA tests revealed widespread allele sharing across species boundaries, a pattern that can be confidently attributed to genetic introgression as opposed to incomplete lineage sorting. These results confirm previous assertions that the evolutionary history of Rhinella was characterized by various levels of hybridization even across environmentally heterogeneous regions, posing exciting questions about what factors prevent complete fusion of diverging yet highly interdependent evolutionary lineages. (AU)

• FAPESP's process: 13/50297-0 - Dimensions US-BIOTA São Paulo: a multidisciplinary framework for biodiversity prediction in the Brazilian Atlantic forest hotspot
• Grantee: Cristina Yumi Miyaki
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 12/15754-8 - Ecogeographical consequences of evolution of the snake-like morphotype in squamates
• Grantee: Agustín Camacho Guerrero
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 03/10335-8 - Systematics and evolution of the herpetological fauna from Neotropical areas
• Grantee: Miguel Trefaut Urbano Rodrigues
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 17/08357-6 - Phylogenetic Endemism and Comparative Phylogeography of the Brazilian Amazon Herpetofauna
• Grantee: Sérgio Marques de Souza
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 11/50206-9 - Origin and evolution of snakes and their diversification in the Neotropics: a multidisciplinary approach
• Grantee: Hussam El Dine Zaher
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 11/50146-6 - Comparative phylogeography, phylogeny, paleoclimate modeling, and taxonomy of neotropical reptiles and amphibians
• Grantee: Miguel Trefaut Urbano Rodrigues
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants