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Evolutionary history and population genetics of a cyprinid fish (Iberochondrostoma olisiponensis) endangered by introgression from a more abundant relative
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Orientador(es)
Resumo(s)
The use of molecular techniques has shown that
hybridization and introgression have significant impacts in
evolution, by means of transfer of genetic variation and
formation of hybrid species. In this paper we use mitochondrial
and nuclear sequence data to investigate the
evolutionary history, levels of genetic diversity and population
differentiation of a rare and endangered fish species.
Our results suggest that a hybrid origin scenario of Chondrostoma
olisiponensis is a likely explanation for the
shared genetic and morphological traits with Iberochondrostoma
and Achondrostoma ? Pseudochondrostoma. The
basal positioning of C. olisiponensis alleles in all loci
analyzed indicates that hybridization events occurred
before differentiation within each of these groups, most
likely during Middle–Late Miocene. Originally described
as C. olisiponensis, we suggest that this species should be
placed in the genus Iberochondrostoma to avoid confusion
with ‘real’ central European Chondrostoma and to
(partially) reflect its evolutionary history. Analyses of
levels of genetic diversity and patterns of population subdivision
show that populations of the rare Iberochondrostoma
olisiponensis are differentiated (high and significant
uST and FST) and genetically depauperate (very low S, p,
and h). I. olisiponensis is simultaneously imperiled by
small population sizes and contemporary bidirectional
hybridization with another critically endangered sympatric
species (Iberochondrostoma lusitanicum). Urgent ex-situ
conservation measures involving supportive breeding of I.
olisiponensis are needed to preserve present genetic variation
and eventually increase in situ population sizes, along
with further studies focused on different life history and
behavioral characteristics of this highly endangered species.
Descrição
Palavras-chave
Intergeneric hybridization Introgression Hybrid speciation Cyprinidae Parental species displacement Mito-nuclear discordance
Contexto Educativo
Citação
Conservation Genetics, 15, 665-677
Editora
Springer