RADseq data reveal widespread historical introgression in four familiar North American songbirds.

Population genetic structure is influenced by a combination of contemporary and historical events; however, this structure can be complicated by ongoing gene flow. While it is well known that contemporary hybridization occurs frequently among many closely related species, it often remains uncertain as to which populations are involved in introgression events, and this can be even more difficult to infer when introgression is historical. Here we use restriction-site associated DNA sequencing to look at the level of introgression among four species of songbirds in North America: the black-capped, mountain, boreal, and chestnut-backed chickadee.

A survey of molecular diversity and population genetic structure in North American clearwing moths (Lepidoptera: Sesiidae) using cytochrome c oxidase I.

The phylogeographic structure of insect species in North America is poorly understood. The moth family Sesiidae (Lepidoptera) contains many economically important pests of agriculture and forestry, as well as beneficial species used in biological control. Despite their significance, this study constitutes the first broad-ranging population genetic study on North American sesiids.

Phylogeographic mitogenomics of Atlantic cod : Variation in and among trans-Atlantic, trans-Laurentian, Northern cod, and landlocked fjord populations.

The historical phylogeography, biogeography, and ecology of Atlantic cod () have been impacted by cyclic Pleistocene glaciations, where drops in sea temperatures led to sequestering of water in ice sheets, emergence of continental shelves, and changes to ocean currents. High-resolution, whole-genome mitogenomic phylogeography can help to elucidate this history. We identified eight major haplogroups among 153 fish from 14 populations by Bayesian, parsimony, and distance methods, including one that extends the species coalescent back to ca.

Intraspecific mitogenomics of three marine species-at-risk: Atlantic, spotted, and northern wolffish (Anarhichas spp.).

High-resolution mitogenomics of within-species relationships can answer such phylogeographic questions as how species survived the most recent glaciation, as well as identify contemporary factors such as physical barriers, isolation, and gene flow. We examined the mitogenomic population structure of three at-risk species of wolffish: Atlantic (Anarhichas lupus), spotted (A. minor), and northern (A.

Phylogeographic structure in three North American tent caterpillar species (Lepidoptera: Lasiocampidae): , , and .

While phylogeographic structure has been examined in many North American vertebrate species, insects have received much less attention despite their central ecological roles. The moth genus (Hübner, 1820), is an important group of forestry pests responsible for large-scale defoliation across much of the Nearctic and Palearctic. The present study uses sequence variation in the mitochondrial cytochrome oxidase 1 (COI) gene to examine the population genetic structure of the three widespread species (, , and ).

Exploring the limits of nucleobase expansion: computational design of naphthohomologated (xx-) purines and comparison to the natural and xDNA purines.

The properties of doubly-expanded (xx-) purine analogues are compared to the natural and singly-expanded (x-) purines using quantum chemical (B3LYP, MP2) methods. Purine expansion upon incorporation of a benzene or naphthalene spacer affects the preferred orientation of the base about the glycosidic bond in the corresponding nucleoside to a similar extent. Although the natural purines preferentially adopt the anti orientation with respect to the 2'-deoxyribose moiety, the syn and anti conformations are almost isoenergetic in the case of the expanded analogues.

yDNA versus yyDNA pyrimidines: computational analysis of the effects of unidirectional ring expansion on the preferred sugar-base orientation, hydrogen-bonding interactions and stacking abilities.

The properties of natural, y- and yy-pyrimidines are compared using computational (B3LYP, MP2) methods. Ring expansion upon incorporation of benzene or naphthalene into the natural pyrimidines affects the preferred orientation of the base about the glycosidic bond in the corresponding nucleoside to a similar extent. Specifically, although the natural pyrimidines preferentially adopt the anti orientation with respect to the 2'-deoxyribose moiety, the expanded analogues will likely display (anti/syn) conformational heterogeneity, which may lead to alternate hydrogen-bonding modes in double-stranded duplexes.

yDNA versus xDNA pyrimidine nucleobases: computational evidence for dependence of duplex stability on spacer location.

The structural and binding properties of the natural and x- and y-pyrimidines were compared using computational methods. Our calculations show that although the x-pyrimidines favor different orientations about the glycosidic bond compared to the natural pyrimidines, which could have implications for the formation and resulting stability of xDNA duplexes and jeopardize the selectivity of expanded nucleobases, y-pyrimidines have rotational profiles more similar to the natural bases. Increasing the pyrimidine size using a benzene spacer leads to relatively minor changes in the hydrogen-bond strength of isolated Watson-Crick base pairs.