Tufted Puffins exhibit low levels of genetic differentiation among breeding colonies in North America

Tufted Puffins (Fratercula cirrhata) are experiencing population declines in some parts of their distribution, making this a species of increased conservation interest. Genetic data will help to identify Tufted Puffin populations of conservation importance and provide an important tool for developing conservation management plans. This species is broadly distributed across the North Pacific Ocean but little is known about the extent of genetic variation and differentiation across their range. In this study, we examine mitochondrial DNA (mtDNA), 8 microsatellite loci and 1,260 single nucleotide polymorphisms (SNPs) to determine the extent of gene flow among 7 breeding colonies (Oregon to the western Aleutians) in the North American breeding range of the species and identify potential barriers to dispersal. Our results show that most breeding colonies form a single genetic cluster, and mtDNA data show substantial historical gene flow among populations. For the microsatellite dataset, all F-ST comparisons that include St. Lazaria, in southeast Alaska, except Oregon, which had a small sample size, were significant as were comparisons between Triangle Island and the two westernmost sampling sites of Buldir and Aiktak. For the SNP dataset, F-ST comparisons were low and nonsignificant, further suggesting that breeding colonies form a single panmictic population. Individuals were more closely related to individuals from the same colony, and we found a weak relationship between genetic and geographic distance. This suggests that dispersal among colonies is high, likely facilitated by an overlap in wintering ranges among colonies. The high connectivity among breeding colonies indicates that Tufted Puffins form a single conservation unit, although future genetic studies should incorporate a whole genome sequencing approach to assessing how functional genetic diversity varies across their distribution. Lay Summary & BULL; Tufted Puffins (Fratercula cirrhata) are experiencing population declines in some parts of their distribution, making this a species of increased conservation interest. & BULL; Here we use 3 different types of genetic markers (mtDNA, microsatellites, and SNPs) to examine population genetic structure among 7 breeding colonies (Oregon to the western Aleutians) in the North American breeding range of the species. & BULL; We examined population genetic structure to determine whether Tufted Puffin populations form single or multiple conservation units. & BULL; All 3 types of markers showed a similar pattern and indicate that North American breeding colonies form a single genetic cluster. & BULL; Our results suggest that dispersal among colonies is high, likely facilitated by an overlap in wintering ranges among colonies. & BULL; The high connectivity among breeding colonies indicates that Tufted Puffins form a single conservation unit, although future genetic studies should include samples from Asia to assess population genetic structure across their whole distribution.