User:Claireemmacho/Northern elephant seal

Article Draft
Northern Elephant Seals

Nevertheless, a genetic bottleneck experienced by Northern elephant seals during the nineteenth century made them more susceptible to disease, environmental changes and pollution. This bottleneck caused a sharp loss of genetic diversity and increased homozygosity in the surviving population, and also a decreased number of haplogroups.

New-

While the population may have recovered, the genetic diversity of the species did not, resulting in a genetic bottleneck. The bottleneck resulted in both behavioral and genetic effects within the population. Believing to had occurred in 1884 when the population was estimated to be under 20 individuals, the currently population of Northern Elephant Seals suffer many consequences of inbreeding.

A major consequence of inbreeding has been physical changes to Northern Elephant Seals physiology. Compared to skulls prior to the bottleneck, modern elephant seal skulls have a high rate of asymmetry which can affect normal functions of the brain. Genetically, the loss of rare alleles during the bottleneck led to a deficit of alleles relative to the number of heterozygotes, as well as decreased the number of haplogroups and evidently, resulted in a loss of genetic diversity.

These physical and genetic changes have led to an overall decrease in population stability. The loss of genetic variation makes the population more susceptible to disease and environmental changes, and also results in an overall loss in developmental stability. The lack of diversity means that a larger percentage of the population will be negatively affected if any change were to occur. So while though this population has recovered, the near extinction event has forever changed their genetic makeup and future survival.

- This is due to the sudden loss of rare alleles at the time of the bottleneck, and the resulting deficit of alleles relative to the number of heterozygotes.

- A third factor is the potential disruption of pleiotropic interactions. Inbred populations tend to have high levels of morphometric variation

- reduced polymorphism reduces the evolutionary potential of a population to respond to a changing environment

- modern vs pre bottleneck skulls show a significant increase in asymmetry

- bottleneck is assumed to occur in 1884

- most likely bottleneck according to multiple simulations and tests, was a bottleneck of less than 20 seals

- loss of polymorphism, heterozygosity, and developmental stability