On the other hand, genetic pauperization and isolation of two other populations in connection with extremely small population sizes and unfavourable habitat conditions seem to reflect recent bottlenecks.
Phylogenetic studies frequently detect separate lineages in Europe which reflect population bottlenecks, isolation in glacial refugia, and subsequent recolonisation.
This perceived reduction in variation has been assumed to reflect a bottleneck and subsequent reduction in genetic variation at founding.
The exception is a clade of Australasian individuals, which may reflect a bottleneck during their recent introduction to this region.
Lower genetic diversity in cave populations than in related surface populations probably reflects smaller effective population sizes because of food and space limitations, but may also reflect possible bottleneck events due to periodic droughts and other environmental fluctuations [ 7].
This interpretation is strengthened given the shape of the human mtDNA tree, which reflects the bottlenecks and subsequent population expansions associated with the out-of-Africa migration and the hectic climatic conditions of the last glacial period.
Coral reef fishes generally display large effective population sizes [ 49] and many marine fishes are characterised by relatively shallow population genetic structures reflecting genetic bottlenecks associated with Pleistocene climate variation [reviewed by [ 50, 51]].
In the paper, they mentioned "individuals from populations with substantial African ancestry (YRI, LWK and ASW) carry up to three times as many low-frequency variants (0.5-5% frequency) as those of European or East Asian origin, reflecting ancestral bottlenecks in non-African populations".
Elevated linkage disequilibrium (LD) and enriched homozygosity found in OAs reflect isolation and bottlenecks experienced.
Examining the proportion of heterozygous loci in table 5, Yak appears to be more heterozygous than Bison, which may reflect past population bottlenecks in Bison [ 29, 30].
Consequently, disparities persist and reflect barriers and bottlenecks to scaling-up quality health care for women and newborns in low-resource contexts [ 3, 4].
