A widely accepted paradigm is that sedentary Neotropical bird species are a reservoir that gives rise to temperate-tropical migratory species. Recently, an alternative theory has been proposed, that developmental plasticity can allow some individuals within a migratory species to establish a disjunct breeding range through loss of migration, thus facilitating the founding of a new sedentary species. We used mtDNA and two nuclear introns to perform coalescent analyses for two closely related New World oriole species, one a long-distance temperate-tropical migrant and the other a short-distance intratropical migrant. Our results suggest that the short-distance migrant recently diverged from the long-distance migrant via a founder event. In this species pair, the widely accepted paradigm is not supported. These results are consistent with a model of speciation through reduction of migratory distance.

Endogenous feline leukemia viruses (enFeLVs) occur in the germ lines of the domestic cat and related wild species (genus Felis). We sequenced the long terminal repeats and part of the env region of enFeLVs in domestic cats and five wild species. A total of 305 enFeLV sequences were generated across 17 individuals, demonstrating considerable diversity within two major clades. Distinct proliferations of enFeLVs occurred before and after the black-footed cat diverged from the other species. Diversity of enFeLVs was limited for the sand cat and jungle cat suggesting that proliferation of enFeLVs occurred within these species after they diverged. Relationships among enFeLVs were congruent with host species relationships except for the jungle cat, which carried only enFeLVs from a lineage that recently invaded the germline (enFeLV-AGTT). Comparison of wildcat and domestic cat enFeLVs indicated that a distinctive germ line invasion of enFeLVs has not occurred since the cat was domesticated.

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