Mito-nuclear discordance in the evolutionary history of a widespread passerine (Troglodytes aedon).

TUBARO, P. L.; KOPUCHIAN, C.; LIJTMAER, D. A.; CAMPAGNA L.

Puerto Iguazú - Misiones

Congreso; Ornithological Congress of the Americas - XVII RAO - XXIV CBO - XCV AFO; 2017

Association of Field Ornithologists - Aves Argentinas - Sociedad Brasilia de Ornitología

Divergent intraspecific lineages discovered in mitochondrial-based analyses are frequently interpreted as being isolated with limited gene flow. However, nuclear markers are better suited to uncover patterns of gene flow and can be easily obtained at large scale using genomic techniques. Here we combine mitochondrial and genomic (ddRADseq) data to study the evolutionary history of the House Wren, Troglodytes aedon, focusing on the southern cone of South America. Mitochondrial (COI) data from around 90 specimens from Argentina, Bolivia and Uruguay revealed the presence of at least 3 continental lineages with up to 5% sequence divergence. These lineages, however, were not geographically structured: only one lineage is present in Patagonia but two or three different lineages are sympatric in other localities in Argentina. Our genomic analysis did not differentiate these lineages as clearly as the mitochondria, with the exception of a few birds from the High Andes in Bolivia, and instead suggested high levels of gene flow among lineages. Moreover, the subtle nuclear differentiation could be partially explained by isolation by distance. These results suggest the presence of divergent mitochondrial lineages in a largely panmictic population. This pattern could be due to ancient isolation and posterior secondary contact with gene flow among lineages, and the very large effective population size of this species could also contribute to the retention of mitochondrial diversity. This study highlights that analyzing nuclear and mitochondrial data together provides a better understanding of evolutionary history and emphasizes the need for precaution when interpreting mitochondrial patterns on their own.