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Genomic trajectories of a near-extinction event in the Chatham Island black robin.
von Seth, Johanna; van der Valk, Tom; Lord, Edana; Sigeman, Hanna; Olsen, Remi-André; Knapp, Michael; Kardailsky, Olga; Robertson, Fiona; Hale, Marie; Houston, Dave; Kennedy, Euan; Dalén, Love; Norén, Karin; Massaro, Melanie; Robertson, Bruce C; Dussex, Nicolas.
Afiliação
  • von Seth J; Centre for Palaeogenetics, Svante Arrhenius Väg 20C, 106 91, Stockholm, Sweden. johanna.n.vonseth@gmail.com.
  • van der Valk T; Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden. johanna.n.vonseth@gmail.com.
  • Lord E; Department of Zoology, Stockholm University, 106 91, Stockholm, Sweden. johanna.n.vonseth@gmail.com.
  • Sigeman H; Centre for Palaeogenetics, Svante Arrhenius Väg 20C, 106 91, Stockholm, Sweden.
  • Olsen RA; Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden.
  • Knapp M; Centre for Palaeogenetics, Svante Arrhenius Väg 20C, 106 91, Stockholm, Sweden.
  • Kardailsky O; Department of Bioinformatics and Genetics, Swedish Museum of Natural History, Stockholm, Sweden.
  • Robertson F; Department of Zoology, Stockholm University, 106 91, Stockholm, Sweden.
  • Hale M; Department of Biology, Lund University, Ecology Building, 223 62, Lund, Sweden.
  • Houston D; Ecology and Genetics Research Unit, University of Oulu, 90014, Oulu, Finland.
  • Kennedy E; Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, 17121, Solna, Sweden.
  • Dalén L; Department of Anatomy, University of Otago, Dunedin, 9054, New Zealand.
  • Norén K; Coastal People Southern Skies Centre of Research Excellence, University of Otago, PO Box 56, Dunedin, 9054, Aotearoa, New Zealand.
  • Massaro M; Department of Anatomy, University of Otago, Dunedin, 9054, New Zealand.
  • Robertson BC; Department of Zoology, University of Otago, Dunedin, 9054, New Zealand.
  • Dussex N; School of Biological Sciences, University of Canterbury, Christchurch, 8140, New Zealand.
BMC Genomics ; 23(1): 747, 2022 Nov 10.
Article em En | MEDLINE | ID: mdl-36357860
ABSTRACT

BACKGROUND:

Understanding the micro--evolutionary response of populations to demographic declines is a major goal in evolutionary and conservation biology. In small populations, genetic drift can lead to an accumulation of deleterious mutations, which will increase the risk of extinction. However, demographic recovery can still occur after extreme declines, suggesting that natural selection may purge deleterious mutations, even in extremely small populations. The Chatham Island black robin (Petroica traversi) is arguably the most inbred bird species in the world. It avoided imminent extinction in the early 1980s and after a remarkable recovery from a single pair, a second population was established and the two extant populations have evolved in complete isolation since then. Here, we analysed 52 modern and historical genomes to examine the genomic consequences of this extreme bottleneck and the subsequent translocation.

RESULTS:

We found evidence for two-fold decline in heterozygosity and three- to four-fold increase in inbreeding in modern genomes. Moreover, there was partial support for temporal reduction in total load for detrimental variation. In contrast, compared to historical genomes, modern genomes showed a significantly higher realised load, reflecting the temporal increase in inbreeding. Furthermore, the translocation induced only small changes in the frequency of deleterious alleles, with the majority of detrimental variation being shared between the two populations.

CONCLUSION:

Our results highlight the dynamics of mutational load in a species that recovered from the brink of extinction, and show rather limited temporal changes in mutational load. We hypothesise that ancestral purging may have been facilitated by population fragmentation and isolation on several islands for thousands of generations and may have already reduced much of the highly deleterious load well before human arrival and introduction of pests to the archipelago. The majority of fixed deleterious variation was shared between the modern populations, but translocation of individuals with low mutational load could possibly mitigate further fixation of high-frequency deleterious variation.
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Texto completo: 1 Base de dados: MEDLINE Assunto principal: Deriva Genética / Endogamia Idioma: En Ano de publicação: 2022 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Deriva Genética / Endogamia Idioma: En Ano de publicação: 2022 Tipo de documento: Article