120 research outputs found
The fitness consequences of inbreeding in natural populations and their implications for species conservation – a systematic map
Background: Threatened species often have small and isolated populations where mating among relatives can
result in inbreeding depression increasing extinction risk. Effective management is hampered by a lack of syntheses
summarising the magnitude of, and variation in inbreeding depression. Here we describe the nature and scope
of the literature examining phenotypic/fitness consequences of inbreeding, to provide a foundation for future
syntheses and management.
Methods: We searched the literature for articles documenting the impact of inbreeding in natural populations.
Article titles, abstracts and full-texts were assessed against a priori defined criteria, and information relating to study
design, quality and other factors that may influence inbreeding responses (e.g. population size) was extracted from
relevant articles.
Results: The searches identified 11457 articles, of which 614 were assessed as relevant and included in the systematic
map (corresponding to 703 distinct studies). Most studies (663) assessed within-population inbreeding resulting from
self-fertilisation or consanguineous pairings, while 118 studies assessed among-population inbreeding due to drift load.
Plants were the most studied taxon (469 studies) followed by insects (52 studies) and birds (43 studies). Most studies
investigated the effects of inbreeding on components of fitness (e.g. survival or fecundity; 648 studies) but measurements
were typically under laboratory/greenhouse conditions (486 studies). Observations were also often restricted to the first
inbred generation (607 studies) and studies frequently lacked contextual information (e.g. population size).
Conclusions: Our systematic map describes the scope and quality of the evidence describing the phenotypic
consequences of inbreeding. The map reveals substantial evidence relating to inbreeding responses exists,
but highlights information is still limited for some aspects, including the effects of multiple generations of
inbreeding. The systematic map allowed us to define several conservation-relevant questions, where sufficient
data exists to support systematic reviews, e.g. How do inbreeding responses vary with population size? However,
we found that such syntheses are likely to be constrained by incomplete reporting of critical contextual information.
Our systematic map employed the same rigorous literature assessment methods as systematic review, including a
novel survey of study quality and thus provides a robust foundation to guide future research and syntheses seeking to
inform conservation decision-making
Genetic variability and structure of jaguar (Panthera onca) in Mexican zoos
ArtÃculoGenealogical records of animals (studbook) are
created to avoid reproduction between closely related
individuals, which could cause inbreeding, particularly for
such endangered species as the Panthera onca (Linnaeus,
1758). Jaguar is the largest felid in the Americas and is
considered an important ecological key species. In Mexico,
wild jaguar populations have been significantly reduced in
recent decades, and population decline typically accompany decreases in genetic variation. There is no current
census of captive jaguars in Mexico, and zoos do not follow a standardized protocol in breeding programs based on
genetic studies. Here, we emphasise the importance of
maintaining an adequate level of genetic variation and
propose the implementation of standardised studbooks for
jaguars in Mexico, mainly to avoid inbreeding. In addition,
achieving the aims of studbook registration would provide
a population genetic characterisation that could serve as a
basis for ex situ conservation programmes
Selection for Heterozygosity Gives Hope to a Wild Population of Inbred Wolves
Recent analyses have questioned the usefulness of heterozygosity estimates as measures of the inbreeding coefficient (f), a finding that may have dramatic consequences for the management of endangered populations. We confirm that f and heterozygosity is poorly correlated in a wild and highly inbred wolf population. Yet, our data show that for each level of f, it was the most heterozygous wolves that established themselves as breeders, a selection process that seems to have decelerated the loss of heterozygosity in the population despite a steady increase of f. The markers contributing to the positive relationship between heterozygosity and breeding success were found to be located on different chromosomes, but there was a substantial amount of linkage disequilibrium in the population, indicating that the markers are reflecting heterozygosity over relatively wide genomic regions. Following our results we recommend that management programs of endangered populations include estimates of both f and heterozygosity, as they may contribute with complementary information about population viability
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