Quantifying and managing the loss of genetic variation in a free-ranging population of takahe through the use of pedigrees |
| |
Authors: | Catherine E Grueber Ian G Jamieson |
| |
Institution: | (1) Department of Zoology, University of Otago, 340 Great King Street, P.O. Box 56, Dunedin, New Zealand |
| |
Abstract: | Pedigree analysis has clear benefits for the genetic management of threatened populations through the evaluation of inbreeding,
population structure and genetic diversity. The use of pedigrees is usually restricted to captive populations and few examples
exist of their exclusive use in managing free-ranging populations. One such example is the management of the takahe (Porphyrio hochstetteri), a highly endangered, flightless New Zealand rail at risk from introduced mammalian predators and habitat loss. During the
1980’s and 90’s, as part of the takahe recovery programme, birds were translocated from the sole remnant population in Fiordland
to four offshore islands from which introduced predators had been eradicated. The subsequent “island” population, now numbering
83 and thought to be at carrying capacity, has been closely monitored since founding. Detailed breeding records allow us to
analyse the island pedigree, which is up to 7 generations deep. Gene-drop analysis indicated that 7.5% of genetic diversity
has been lost over the relatively short timeframe since founding (2.1 generations on average; total genetic founders = 31)
due to both a failure to equalise founder representation early on and subsequent disproportionate breeding success (founder
equivalents = 12.5; founder genome equivalents = 6.6). A high prevalence of close inbreeding will have also impacted on genetic
diversity. Predictions from pedigree modelling suggest that 90% genetic diversity will be maintained for only 12 years, but
by introducing a low level of immigration from the Fiordland population and permitting the population to grow, 90% GD could
be maintained over the next 100 years. More generally, the results demonstrate the value of maintaining pedigrees for wild
populations, especially in the years immediately after a translocation event. |
| |
Keywords: | Founders Genetic diversity Heterozygosity Porphyrio hochstetteri Threatened species |
本文献已被 SpringerLink 等数据库收录! |
|