Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 2 de 2
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Ano de publicação
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
Ann Bot ; 123(3): 505-519, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30307538

RESUMO

BACKGROUND AND AIMS: Alpine oceanic ecosystems are considered amongst the most ephemeral and restricted habitats, with a biota highly vulnerable to climate changes and disturbances. As an example of an alpine insular endemic, the past and future population genetic structure and diversity, and the future distribution of Viola cheiranthifolia (Violaceae), endemic to Tenerife (Canary Islands), were estimated. The main goals were to predict distribution changes of this alpine oceanic plant under climate change, and to assist in actions for its conservation. METHODS: To perform population genetic analysis, 14 specific microsatellite markers and algorithms which considered the polyploid condition of V. cheiranthifolia were employed. The niche modelling approach incorporated temperature gradients, topography and snow cover maps. Models were projected into climate change scenarios to assess the extent of the altitudinal shifts of environmental suitability. Finally, simulations were performed to predict whether the environmental suitability loss will affect the genetic diversity of populations. KEY RESULTS: Viola cheiranthifolia presents short dispersal capacity, moderate levels of genetic diversity and a clear population genetic structure divided into two main groups (Teide and Las Cañadas Wall), showing signs of recolonization dynamics after volcanic eruptions. Future estimates of the distribution of the study populations also showed that, despite being extremely vulnerable to climate change, the species will not lose all its potential area in the next decades. The simulations to estimate genetic diversity loss show that it is correlated to suitability loss, especially in Las Cañadas Wall. CONCLUSIONS: The low dispersal capacity of V. cheiranthifolia, coupled with herbivory pressure, mainly from rabbits, will make its adaptation to future climate conditions in this fragile alpine ecosystem difficult. Conservation actions should be focused on herbivore control, population reinforcement and surveillance of niche shifts, especially in Guajara, which represents the oldest isolated population and a genetic reservoir for the species.


Assuntos
Mudança Climática , Conservação dos Recursos Naturais , Ecossistema , Variação Genética , Dispersão Vegetal , Viola/fisiologia , Teorema de Bayes , Espécies em Perigo de Extinção , Ilhas , Modelos Biológicos , Modelos Genéticos , Dinâmica Populacional , Espanha , Viola/genética
2.
Asian-Australas J Anim Sci ; 28(1): 25-36, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25557673

RESUMO

The complex analysis of the pedigree records of Czech Landrace (CLA), Czech Large White-dam line (CLWd), Czech Large White-sire line (CLWs), Duroc (DC), and Pietrain (PN) was performed to determine trends of genetic diversity (GD), and to find the main sources of the GD loss. The total size of the pedigree was 132,365, 391,151, 32,913, 13,299, and 7,160 animals in CLA, CLWd, CLWs, DC, and PN, respectively. Animals born in the years 2011 through 2013 were assumed as the reference population. The average pedigree completeness index for one generation back was 95.9%, 97.4%, 91.2%, 89.8%, and 94.2% for appropriate breeds. Number of ancestors explaining 100% of gene pool was 186, 373, 125, 157, and 37 in CLA, CLWd, CLWs, DC, and PN, respectively. The relative proportion of inbred animals (58%, 58%, 54%, 47%, and 25%), the average inbreeding (2.7%, 1.4%, 2.5%, 3.6%, and 1.3%) and the average co-ancestry (3.1%, 1.6%, 3.3%, 4.2%, and 3.3%) were found over the past decade in analysed breeds. The expected inbreeding under random mating increased during the last 10 years in CLWs and PN and varied from 1.27% to 3.2%. The effective population size computed on the basis of inbreeding was 76, 74, 50, 35, and 83 in 2012 in CLA, CLWd, CLWs, DC, and PN, respectively. The shortest generation interval (1.45) was observed for CLWd in sire to son selection pathway. The longest generation interval obtained PN (1.95) in sire to daughter pathway. The average relative GD loss within last generation interval was 7.05%, 4.70%, 9.81%, 7.47%, and 10.46%, respectively. The relative proportion of GD loss due to genetic drift on total GD loss was 85.04%, 84.51%, 89.46%, 86.19%, and 83.68% in CLA, CLWd, CLWs, DC, and PN, respectively. All breeds were characterized by a high proportion of inbred animals, but the average inbreeding was low. The most vulnerable breeds to loss of GD are DC and PN. Therefore, a breeding program should be more oriented to prevent the increase of GD loss in these breeds.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA