Unexpectedly high genetic diversity of mtDNA control region through severe bottleneck in vulnerable albatross Phoebastria albatrus

Abstract

In the late part of the nineteenth century and the early part of the last century, the short-tailed albatross Phoebastria albatrus was in danger of extinction owing to feather hunting. In the middle of the last century, the total number of this species was inferred to be approximately 50-60 with breeding occurring only on Torishima Island of the Izu Islands. Recently, the number of individuals has increased to more than 2,000 and that of their breeding islands to three, namely, Torishima Island, and Minamiand Kita-kojima Islands of the Senkaku Islands. Here, we show that the 44 short-tailed albatrosses we examined represent 29 haplotypes in the control region of mitochondrial DNA, and have a considerably higher genetic diversity than most avian species, but not very high in albatross species; the h and p were 0.96 and 0.013, respectively. However, the parsimony network clearly showed that many intermediate haplotypes were lost. It was concluded that the majority of the haplotypes in the founder population have been maintained. Judging from these findings and the exponential increase in the number of individuals, the present population of the short-tailed albatross seems not to be affected by inbreeding depression through a severe bottleneck. The conservation and expansion of their breeding grounds, and effective protection from bycatch mortality in foraging areas are important for the future survival of this species.

Mosaic gene conversion after a tandem duplication of mtDNA sequence in Diomedeidae (albatrosses)

“…The samples were also analyzed as part of a conservation genetic study of the species and selected to represent two distinct clades (Kuro-o et al, 2010). Muscle samples from three P. immutabilis individuals and one P. nigripes were collected in the northern Pacific and on Chichi-jima, one of the Bonin Islands.…”

“…The root of each feather was sliced into small fragments with clean scissors. Whole genomic DNA was extracted from the P. albatrus feathers sampled from chicks using phenol-chloroform, as described by Kuro-o et al (2010). An IsoQuick Nucleic Acid Extraction Kit (ORCA Research) was used to extract genomic DNA from the other samples, as described by Eda et al (2008).…”

Ontogenetic changes in at-sea distributions of immature short-tailed albatrosses Phoebastria albatrus

“…Yet, no birds entered the EEZ surrounding the Senkaku Islands, where there is a colony of short-tailed albatrosses that show genetic separation from the population breeding on Torishima (Kuro-o et al 2010). The lack of exploration of these waters and waters even farther west in the subtropical marginal seas that were formerly used by short-tailed albatrosses (Hase gawa & DeGange 1982) suggests the potential for colony level at-sea segregation, particularly in these regions.…”

Museum collections reveal that Buff-breasted Sandpipers (Calidris subruficollis) maintained mtDNA variability despite large population declines during the past 135 years

“…While we expected to see a signal of declining genetic variation, other studies have also found mtDNA variation to be stable in species with declining populations (Brown et al 2007;Kuro-o et al 2010;Reding et al 2010). In these species, high levels of mtDNA variation were likely maintained because historical populations had high genetic variation or large effective population sizes prior to declines and because populations recovered or stabilized quickly once these species were managed.…”