Genetic, Ecological and Morphological Divergence between Populations of the Endangered Mexican Sheartail Hummingbird (Doricha eliza)

Abstract

The Mexican Sheartail (Doricha eliza), an endangered hummingbird, is endemic to Mexico where two populations have a disjunct distribution. One population is distributed along the northern tip of the Yucatan Peninsula whereas the other is mostly restricted to central Veracruz. Despite their disjunct distribution, previous work has failed to detect morphological or behavioral differences between these populations. Here we use variation in morphology, mtDNA and nuDNA sequences to determine the degree of morphological and molecular divergence between populations, their divergence time, and historical demography. We use species distribution modeling and niche divergence tests to infer the relative roles of vicariance and dispersal in driving divergence in the genus. Our Bayesian and maximum likelihood phylogenetic analyses revealed that Doricha eliza populations form a monophyletic clade and support their sister relationship with D. enicura. We found marked genetic differentiation, with reciprocal monophyly of haplotypes and highly restricted gene flow, supporting a history of isolation over the last 120,000 years. Genetic divergence between populations is consistent with the lack of overlap in environmental space and slight morphological differences between males. Our findings indicate that the divergence of the Veracruz and Yucatan populations is best explained by a combination of a short period of isolation exacerbated by subsequent divergence in climate conditions, and that rather than vicariance, the two isolated ranges of D. eliza are the product of recent colonization and divergence in isolation.

Historical and current introgression in a Mesoamerican hummingbird species complex: a biogeographic perspective

“…Increased genomic resources and behavioural data will likely confirm that they constitute separate taxonomic species. These findings are in line with several examples of recent speciation events reported in hummingbird species, some of which show congruent genetic and phenotypic divergence (González, Ornelas & Gutiérrez-Rodríguez, 2011;, while others show genetic divergence and no apparent plumage divergence (Rodríguez-Gó mez, Licona-Vera & Ornelas, 2014;Malpica & Ornelas, 2014). Additional genome-wide markers might help to elucidate the evolutionary history of this young system, in which detecting divergence in a few genes under selection may be critical for proper species delimitation.…”

“…Amplification of ND2 was conducted with primers L5215 and H5578 (Hackett, 1996), whereas for the ATPase 6-8 we used L8929 and H9855 (Sorenson et al, 1999). Protocols for PCR reactions and for sequencing the PCR products are described elsewhere (González, Ornelas & Gutiérrez-Rodrígue, 2011;Licona-Vera & Ornelas, 2014). Sequences were read in a 310 or 3730 automated DNA sequencer (Applied Biosystems, Foster City, CA, USA) at the Instituto de Ecología, A.C. sequencing facility, or at the Evolutionary Genetics Lab in the Museum of Vertebrate Zoology (MVZ).…”

Local adaptation versus historical isolation as sources of melanin‐based coloration in the white‐throated thrushTurdus assimilis

“…Following considerations of Zink and Barrowclough (2008) and considering the objectives of our study, we explored two mitochondrial genes (nicotinamide adenine dinucleotide dehydrogenase subunit 2 gene -ND2 and cytochrome b gene -Cyt B), which were amplified, sequenced and edited following the methodology described in Núñez-Zapata et al (2016). Nuclear genes were excluded considering their ambiguous contribution to the genetic structure of population observed in previous studies for this region (Arbeláez-Cortés et al 2014a, b, Licona-Vera andOrnelas 2014). We supplemented our sampling with published sequences from GenBank of T. assimilis.…”

Peer Review #1 of "Historical and current introgression in a Mesoamerican hummingbird species complex: a biogeographic perspective (v0.1)"

“…Protocols for PCR reactions and for sequencing the PCR products are described elsewhere (González et al, 2011;Licona-Vera & Ornelas, 2014). Sequences were read in a 310 or 3730 automated DNA sequencer (Applied Biosystems) at the Instituto de Ecología, A.C. sequencing facility, or at the Evolutionary Genetics Lab in the Museum of Vertebrate Zoology (MVZ).…”