The Wolf Intelligencer


Wolf Molecular and Genetic Studies

From high masked to high realized genetic load in inbred Scandinavian wolves. Smeds L, Ellegren H. Molecular Ecology. 2022 Jul


When new mutations arise at functional sites they are more likely to impair than improve fitness. If not removed by purifying selection, such deleterious mutations will generate a genetic load that can have negative fitness effects in small populations and increase the risk of extinction. This is relevant for the highly inbred Scandinavian wolf (Canis lupus) population, founded by only three wolves in the 1980s and suffering from inbreeding depression. We used functional annotation and evolutionary conservation scores to study deleterious variation in a total of 209 genomes from both the Scandinavian and neighbouring wolf populations in northern Europe. The masked load (deleterious mutations in heterozygote state) was highest in Russia and Finland with deleterious alleles segregating at lower frequency than neutral variation. Genetic drift in the Scandinavian population led to the loss of ancestral alleles, fixation of deleterious variants and a significant increase in the per-individual realized load (deleterious mutations in homozygote state; an increase by 45% in protein-coding genes) over five generations of inbreeding. Arrival of immigrants gave a temporary genetic rescue effect with ancestral alleles re-entering the population and thereby shifting deleterious alleles from homozygous into heterozygote genotypes. However, in the absence of permanent connectivity to Finnish and Russian populations, inbreeding has then again led to the exposure of deleterious mutations. These observations provide genome-wide insight into the magnitude of genetic load and genetic rescue at the molecular level, and in relation to population history. They emphasize the importance of securing gene flow in the management of endangered populations.

Cryopreservation of grey wolf (Canis lupus) testicular tissue. Andrae CS, Oliveira EC, Ferraz MA, Nagashima JB. Cryobiology. 2021 Jan


Development of genomic preservation technologies for canids, especially for seasonally breeding species like the grey wolf (Canis lupus), is needed in advance of growing species conservation concerns. Here, we evaluated the efficacy of two cryopreservation protocols – needle immersion vitrification (NIV) and slow freezing (SF) on grey wolf (n = 7) testicular tissue morphology. NIV samples were equilibrated in a 7.5% v/v dimethyl sulfoxide (DMSO or Me2SO) + 7.5% ethylene glycol (EG) solution in minimum essential medium with 20% FBS for 10 min at 4 °C, then exposed to 15% DMSO + 15% EG + 0.5 M sucrose for 10 min at 4 °C before plunging into liquid nitrogen. For slow freezing, we assessed two cryoprotectant (CPA) strategies, DMSO, 15% v/v alone (SF-D) or 7.5% EG + 7.5% DMSO (SF-ED). Following thawing, there were no significant differences in seminiferous tubule area among treatment groups, although all cryopreserved tissues displayed reduced tubule size compared with fresh controls and increased apoptosis, the latter reaching significance for SF-D treated tissues. Slow freezing improved maintenance of testis architecture, with minimal detachment of seminiferous tubule basement membranes post-thaw. Spermatogonia densities were reduced in NIV tissues compared with fresh, with no differences in spermatocyte, spermatid, or Sertoli cell counts, or germ cell marker DDX4+ cell densities among groups. In sum, we conclude that slow freezing better maintained morphology of cryopreserved testicular tissues compared with needle vitrification with 15% each DMSO and EG and 0.5 M sucrose, and that DMSO + EG combination SF supports cell viability. This represents a first step in the development of male gonadal tissue preservation strategies for the grey wolf.

Global Phylogeographic and Admixture Patterns in Grey Wolves and Genetic Legacy of An Ancient Siberian Lineage. Pilot M, Moura AE, Okhlopkov IM, Mamaev NV, Alagaili AN, Mohammed OB, Yavruyan EG, Manaseryan NH, Hayrapetyan V, Kopaliani N, Tsingarska E. Scientific reports. 2019 Nov

Genomic Approaches Reveal an Endemic Subpopulation of Gray Wolves in Southern China. Wang GD, Zhang M, Wang X, Yang MA, Cao P, Liu F, Lu H, Feng X, Skoglund P, Wang L, Fu Q. iScience. 2019 Oct

Light and scanning electron microscopic study of lingual papillae in the wolf (Canis lupus). Haligur A, Ozkadif S, Alan A. Microscopy research and technique. 2019 May

Conservation genomics illuminates the adaptive uniqueness of North American gray wolves. Hendricks SA, Schweizer RM, Wayne RK. Conservation Genetics. 2019 Feb

Natural re-colonization and admixture of wolves (Canis lupus) in the US Pacific Northwest: challenges for the protection and management of rare and endangered taxa. Hendricks SA, Schweizer RM, Harrigan RJ, Pollinger JP, Paquet PC, Darimont CT, Adams JR, Waits LP, Hohenlohe PA, Wayne RK. Heredity. 2019 Feb

Combining Harvest and Genetics to Estimate Reproduction in Wolves. Clendenin HR, Adams JR, Ausband DE, Hayden JA, Hohenlohe PA, Waits LP. The Journal of Wildlife Management. 2020 Jan

Population genomics of grey wolves and wolf-like canids in North America. Sinding MH, Gopalakrishan S, Vieira FG, Castruita JA, Raundrup K, Jørgensen MP, Meldgaard M, Petersen B, Sicheritz-Ponten T, Mikkelsen JB, Marquard-Petersen U.PLoS genetics. 2018 Nov

Cross-fostering as a conservation tool to augment endangered carnivore populations
EM Gese, WT Waddell, PA Terletzky, CF Lucash… – Journal of Mammalogy, 2018 Oct

On the path to extinction: Inbreeding and admixture in a declining grey wolf population. Gómez‐Sánchez D, Olalde I, Sastre N, Enseñat C, Carrasco R, Marques‐Bonet T, Lalueza‐Fox C, Leonard JA, Vilà C, Ramírez O. Molecular ecology. 2018 Sep

Natural selection and origin of a melanistic allele in North American gray wolves. Schweizer RM, Durvasula A, Smith J, Vohr SH, Stahler DR, Galaverni M, Thalmann O, Smith DW, Randi E, Ostrander EA, Green RE. Molecular biology and evolution. 2018 May

Natural selection and origin of a melanistic allele in North American gray wolves
RM Schweizer, A Durvasula, J Smith, SH Vohr… – Molecular Biology and …, March 2018

Conservation genomics illuminates the adaptive uniqueness of North American gray wolves
SA Hendricks, RM Schweizer, RK Wayne – Conservation Genetics, 2018

Unexpected genetic composition of a reintroduced carnivore population; JA Grauer, JH Gilbert, JE Woodford, D Eklund… – Biological Conservation,  2017 Sep

A new mitochondrial haplotype confirms the distinctiveness of the Italian wolf (Canis lupus) population. Montana L, Caniglia R, Galaverni M, Fabbri E, Randi E. Mammalian Biology. 2017 May

Genomic consequences of intensive inbreeding in an isolated wolf population
Ø Flagstad, C Wikenros, H Sand, H Ellegren, M Kardos… – Nature Ecology & Evolution, 2017 Apr

Studies of wolf x coyote hybridization via artificial insemination. LD Mech, CS Asa, M Callahan, BW Christensen… – PloS one, 2017 Apr

Whole-genome sequence analysis shows that two endemic species of North American wolf are admixtures of the coyote and gray wolf. Cahill JA, Fan Z, Gronau I, Robinson J, Pollinger JP, Shapiro B, Wall J, Wayne RK. Science Advances. 2016 Jul

Whole mitochondrial genomes illuminate ancient intercontinental dispersals of grey wolves (Canis lupus)
Stephan Koblmüller, Carles Vilà, Belen Lorente-Galdos, Marc Dabad, Oscar Ramirez, Tomas Marques-Bonet, Robert K. Wayne4 and Jennifer A. Leonard, Journal of Biogeography. 2016 Jun

Pervasive effects of aging on gene expression in wild wolves. Charruau, P., R. A. Johnston, D. R. Stahler, A. Lea, N. Sny­der-Mackler, D. W. Smith, S. W. Cole, J. Tung, and R. K. Wayne. 2016

Worldwide patterns of genomic variation and admixture in gray wolves. Fan Z, Silva P, Gronau I, Wang S, Armero AS, Schweizer RM, Ramirez O, Pollinger J, Galaverni M, Del-Vecchyo DO, Du L. Genome research. 2016 Feb

Decades of population genetic research reveal the need for harmonization of molecular markers: the grey wolf C anis lupus as a case study. De Groot GA, Nowak C, Skrbinšek T, Andersen LW, Aspi J, Fumagalli L, Godinho R, Harms V, Jansman HA, Liberg O, Marucco F. Mammal Review. 2016 Jan

Targeted capture and resequencing of 1040 genes reveal environmentally driven functional variation in grey wolves. Schweizer RM, Robinson J, Harrigan R, Silva P, Galverni M, Musiani M, Green RE, Novembre J, Wayne RK. Molecular ecology. 2016 Jan

Genetic subdivision and candidate genes under selection in North American grey wolves. Schweizer RM, Vonholdt BM, Harrigan R, Knowles JC, Musiani M, Coltman D, Novembre J, Wayne RK. Molecular Ecology. 2016 Jan

Genetic management and setting recovery goals for Mexican wolves (Canis lupus baileyi) in the wild; LE Harding, J Heffelfinger, D Paetkau, E Rubin… – Biological …, 2016

Genetic distinctiveness of Alexander Archipelago wolves (Canis lupus ligoni). Weckworth BV, Dawson NG, Talbot SL, Cook JA. Journal of Heredity. 2015 Jul

Applying the Bern Convention on the Conservation of European Wildlife and Natural Habitats to the Problem of Hybridization between Wolves (Canis Lupus) and Domestic Dogs: An Analysis and a Proposal for a Standing Committee’s Recommendation. Trouwborst A. InBern Convention on the Conservation of European Wildlife and Natural Habitats, Doc. TPVS/Inf (2014) 2014 Sep

Genome-wide signatures of population bottlenecks and diversifying selection in European wolves. Pilot M, Greco C, Jędrzejewska B, Randi E, Jędrzejewski W, Sidorovich VE, Ostrander EA, Wayne RK. Heredity. 2014 Apr

Unregulated hunting and genetic recovery from a severe population decline: the cautionary case of Bulgarian wolves. Moura AE, Tsingarska E, Dąbrowski MJ, Czarnomska SD, Jędrzejewska B, Pilot M. Conservation Genetics. 2014 Apr

Hetero-zygote advantage in a finite population: black color in wolves. Hedrick, P.W., D.R. Stahler, and D. Dekker. 2014

North-south differentiation and a region of high diversity in European wolves (Canis lupus); AV Stronen, B Jędrzejewska, C Pertoldi, D Demontis, E Randi, PLoS One, 2013 Oct

An account of the taxonomy of North American wolves from morphological and genetic analyses. Chambers SM, Fain SR, Fazio B, Amaral M. North American Fauna. 2012 Oct

Monitoring wolves (Canis lupus) by non-invasive genetics and camera trapping: a small-scale pilot study. Galaverni M, Palumbo D, Fabbri E, Caniglia R, Greco C, Randi E. European Journal of Wildlife Research. 2012 Feb

A novel assessment of population structure and gene flow in grey wolf populations of the Northern Rocky Mountains of the United States. Vonholdt BM, Stahler DR, Bangs EE, Smith DW, Jimenez MD, Mack CM, Niemeyer CC, Pollinger JP, Wayne RK. Molecular ecology. 2010 Oct

Genetic rescue guidelines with examples from Mexican wolves and Florida panthers. Hedrick PW, Fredrickson R. Conservation genetics. 2010 Apr

What is the taxonomic identity of Minnesota wolves?. Mech LD. Canadian Journal of Zoology. 2010 Feb

Molecular and evolutionary history of melanism in North American gray wolves. Anderson TM, Candille SI, Musiani M, Greco C, Stahler DR, Smith DW, Padhukasahasram B, Randi E, Leonard JA, Bustamante CD, Ostrander EA. Science. 2009 Mar

Genetic nature of eastern wolves: past, present and future. Kyle CJ, Johnson AR, Patterson BR, Wilson PJ, Shami K, Grewal SK, White BN. Conservation Genetics. 2006 Apr

Captive breeding and the reintroduction of Mexican and red wolves. Hedrick PW, Fredrickson RJ. Molecular Ecology. 2008 Jan

From the Apennines to the Alps: colonization genetics of the naturally expanding Italian wolf (Canis lupus) population. Fabbri E, Miquel C, Lucchini V, Santini A, Caniglia R, Duchamp C, WEBER JM, Lequette B, Marucco F, Boitani L, Fumagalli L. Molecular ecology. 2007 Apr

Ecological factors influence population genetic structure of European grey wolves. Pilot M, Jedrzejewski W, Branicki W, Sidorovich VE, Jedrzejewska B, Stachura K, Funk SM. Molecular ecology. 2006 Dec

Genetic assessment of the Iberian wolf Canis lupus signatus captive breeding program. Ramirez O, Altet L, Ensenat C, Vila C, Sanchez A, Ruiz A. Conservation Genetics. 2006 Dec

Dynamics of hybridization and introgression in red wolves and coyotes. Fredrickson RJ, Hedrick PW. Conservation Biology. 2006 Aug

Severe inbreeding depression in a wild wolf Canis lupus population. Liberg O, Andrén H, Pedersen HC, Sand H, Sejberg D, Wabakken P, Åkesson M, Bensch S.Biology letters. 2005 Mar

FAST TRACK: Legacy lost: genetic variability and population size of extirpated US grey wolves (Canis lupus). Leonard JA, Vila C, Wayne RK. Molecular Ecology. 2005 Jan

Spatial patterns of demography and genetic processes across the species’ range: null hypotheses for landscape conservation genetics. Vucetich JA, Waite TA. Conservation genetics. 2003 Sep

Population size estimation in Yellowstone wolves with error‐prone noninvasive microsatellite genotypes. Creel S, Spong G, Sands JL, Rotella J, Zeigle J, Joe L, Murphy KM, Smith D. Molecular ecology. 2003 Jul

Mitochondrial DNA extracted from eastern North American wolves killed in the 1800s is not of gray wolf origin. Wilson PJ, Grewal S, McFadden T, Chambers RC, White BN. Canadian Journal of zoology. 2003 May

Successful molecular cloning and nucleotide sequence determination of partial amelogenin (amelx) exon DNA fragment recovered from a mounted taxidermic pelt specimen tentatively identified as an extinct wolf species, Canis lupus hodophilax Temminck, the Japanese wolf and stocked at School of Agriculture and Life Sciences, the University of Tokyo. TACHI C, ENOMOTO T, MATSUBARA Y, UEDA A, HASEGAWA T, MATSUYAMA J, TSUCHIYA M, OHTA M, TANABE Y, SUZUKI T, ENDO H. Journal of Reproduction and Development. 2002

Prey specialization may influence patterns of gene flow in wolves of the Canadian Northwest. Carmichael LE, Nagy JA, Larter NC, Strobeck C. Molecular Ecology. 2001 Dec

Evaluation of d2, a microsatellite measure of inbreeding and outbreeding, in wolves with a known pedigree. Hedrick P, Fredrickson R, Ellegren H. Evolution. 2001

Y chromosome haplotyping in Scandinavian wolves (Canis lupus) based on microsatellite markers. Sundqvist AK, Ellegren H, Olivier M, Vilà C. Molecular Ecology. 2001 Aug

Mitochondrial DNA variability in Italian and East European wolves: detecting the consequences of small population size and hybridization. Randi E, Lucchini V, Christensen MF, Mucci N, Funk SM, Dolf G, Loeschcke V. Conservation Biology. 2000 Apr

DNA profiles of the eastern Canadian wolf and the red wolf provide evidence for a common evolutionary history independent of the gray wolf; Paul J Wilson, Sonya Grewal, Ian D Lawford, Jennifer NM Heal, Angela G Granacki, David Pennock, John B Theberge, Mary T Theberge, Dennis R Voigt, Will Waddell, Robert E Chambers, Paul C Paquet, Gloria Goulet, Dean Cluff, Bradley N White; Canadian Journal of Zoology, 2000

No inbreeding depression observed in Mexican and red wolf captive breeding programs. Kalinowski ST, Hedrick PW, Miller PS. Conservation biology. 1999 Dec

Inbreeding and relatedness in Scandinavian grey wolves Canis lupus. Ellegren H. Hereditas. 1999 Aug

Genetic evaluation of the three captive Mexican wolf lineages. Hedrick PW, Miller PS, Geffen E, Wayne R. Zoo Biology: Published in affiliation with the American Zoo and Aquarium Association. 1997

Pack structure and genetic relatedness among wolf packs in a naturally-regulated population. Meier TJ, Burch JW, Mech LD, Adams LG. Occasional Publication of the Canadian Circumpolar Institute. 1995

Mitochondrial DNA variability of the gray wolf: genetic consequences of population decline and habitat fragmentation. Wayne RK, Lehman N, Allard MW, Honeycutt RL. Conservation Biology. 1992 Dec

Conservation Genetics of the Endangered Isle Royale Gray Wolf; R. K. WAYNE1,*, N. LEHMAN1, D. GIRMAN1, P.J.P. GOGAN2, D. A. GILBERT3, K. HANSEN1, R. O. PETERSON4, U. S. SEAL5, A. EISENHAWER6, L. D. MECH7 andR.J. KRUMENAKER8; Conservation Biology; Volume 5, Issue 1, pages 41–51, March 1991

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