TY - JOUR

T1 - A sliver of the past

T2 - The decimation of the genetic diversity of the Mexican wolf

AU - Taron, Ulrike H.

AU - Salado, Isabel

AU - Escobar-Rodríguez, Mariana

AU - Westbury, Michael V.

AU - Butschkau, Susanne

AU - Paijmans, Johanna L. A.

AU - vonHoldt, Bridgett M.

AU - Hofreiter, Michael

AU - Leonard, Jennifer A.

N1 - Publisher Copyright: © 2021 The Authors. Molecular Ecology published by John Wiley & Sons Ltd.

PY - 2021

Y1 - 2021

N2 - The endangered Mexican wolf (Canis lupus baileyi) is known to carry exceedingly low levels of genetic diversity. This could be (i) the result of long-term evolutionary patterns as they exist at the southernmost limit of the species distribution at a relatively reduced effective size, or (ii) due to rapid population decline caused by human persecution over the last century. If the former, purifying selection is expected to have minimized the impact of inbreeding. If the latter, rapid and recent declines in genetic diversity may have resulted in severe fitness consequences. To differentiate these hypotheses, we conducted comparative whole-genome analyses of five historical Mexican wolves (1907–1917) and 18 contemporary Mexican and grey wolves from North America and Eurasia. Based on whole-genome data, historical and modern Mexican wolves together form a discrete unit. Moreover, we found that modern Mexican wolves have reduced genetic diversity and increased inbreeding relative to the historical population, which was widespread across the southwestern United States and not restricted to Mexico as previously assumed. Finally, although Mexican wolves have evolved in sympatry with coyotes (C. latrans), we observed lower introgression between historical Mexican wolves and coyotes than with modern Mexican wolves, despite similarities in body size. Taken together, our data show that recent population declines probably caused the reduced level of genetic diversity, but not the observed differentiation of the Mexican wolves from other North American wolves.

AB - The endangered Mexican wolf (Canis lupus baileyi) is known to carry exceedingly low levels of genetic diversity. This could be (i) the result of long-term evolutionary patterns as they exist at the southernmost limit of the species distribution at a relatively reduced effective size, or (ii) due to rapid population decline caused by human persecution over the last century. If the former, purifying selection is expected to have minimized the impact of inbreeding. If the latter, rapid and recent declines in genetic diversity may have resulted in severe fitness consequences. To differentiate these hypotheses, we conducted comparative whole-genome analyses of five historical Mexican wolves (1907–1917) and 18 contemporary Mexican and grey wolves from North America and Eurasia. Based on whole-genome data, historical and modern Mexican wolves together form a discrete unit. Moreover, we found that modern Mexican wolves have reduced genetic diversity and increased inbreeding relative to the historical population, which was widespread across the southwestern United States and not restricted to Mexico as previously assumed. Finally, although Mexican wolves have evolved in sympatry with coyotes (C. latrans), we observed lower introgression between historical Mexican wolves and coyotes than with modern Mexican wolves, despite similarities in body size. Taken together, our data show that recent population declines probably caused the reduced level of genetic diversity, but not the observed differentiation of the Mexican wolves from other North American wolves.

KW - bottleneck

KW - carnivore

KW - historical DNA

KW - historical genome

KW - introgression

KW - mitochondria

U2 - 10.1111/mec.16037

DO - 10.1111/mec.16037

M3 - Journal article

C2 - 34161633

AN - SCOPUS:85109379331

VL - 30

SP - 6340

EP - 6354

JO - Molecular Ecology

JF - Molecular Ecology

SN - 0962-1083

IS - 23

ER -