title

Genetic diversity of the free-living population of Przewalski's horses in the Chernobyl Exclusion Zone

author(s)

Ekaterina E. Kheidorova, Kanstantsin V. Homel, Mikhail E. Nikiforov, Aliaksei V. Shpak, Valery Ch. Dombrovski, Marina S. Shkvyrya, Peter E. Schlichting, James C. Beasley, Denis A. Vishnevsky, Yegor B. Yakovlev

affiliation

Scientific and Practical Center for Bioresources, NAS of Belarus (Minsk, Belarus)
Polesie State Radioecological Reserve (Chojniki, Belarus)
Kyiv Zoological Park of National Importance (Kyiv, Ukraine)
University of Georgia (Athens, USA)
Chernobyl Radiation and Ecological Biosphere Reserve (Kyiv, Ukraine)
I.I. Schmalhausen Institute of Zoology, NAS of Ukraine (Kyiv, Ukraine)

bibliography

Theriologia Ukrainica. 2020. Vol. 20: 58–66.

DOI

language

English, with Ukrainian summary, titles of tables, captures to figs

abstract

The present study is aimed at evaluating the genetic diversity, genetic status and the extent of hybridization with the domestic horse for the Przhevalski’s horse (Equus ferus przewalskii Poliakov 1881) population free-ranging in the territory of the Chernobyl Exclusion Zone (CEZ) in Belarus and Ukraine. The sample size included 12 individuals (10 sampled in the Belarusian part of the CEZ and 2 from the Ukrainian part of the CEZ). Ten microsatellites recommended by the International Society for Animal Genetics (ISAG) for horse genetic status and pedigree determination were used as markers in this study. The fragment analysis data obtained utilising this microsatellite panel determined that two individuals from Belarus possess no allelic variants typical for Przhevalski’s horse. Most of the other individuals presented diagnostically valuable allelic variants. Demographic history analysis for the population did not indicate any drastic population shrinkage events in the population’s recent history. The studied population is characterised by heterogeneous population structure with signs of inbreeding (0.21 %), intermediate level of genetic diversity (He = 0.63) and allelic richness (5.15), possesses 16 unique alleles among 2 microsatellite loci and valuable alleles for loci HMS3 and HMS7 (46.4 and 67.9 % specific alleles for Przhevalski’s horse, respectively). Genetic structure evaluation for the population was performed via Bayesian population structure analysis and factorial correspondence analysis (FCA), which indicated the presence of intrapopulation genetic subdivision. Taking into account the obtained indicators of genetic diversity, we may conclude on the relatively favourable status of Przewalski’s horse in the exclusion zone with good potential for the long-term existence of the species population in the wild. In order to minimise inbreeding effects and the risk of a decline in genetic diversity in the population of Przewalski’s horse of the exclusion zone, as well as to increase the value of this free-living group to preserve the gene pool of the species as a whole, it is necessary to provide detailed genetic monitoring of the livestock’s state, as well as develop a regional population management plan, including measures aimed to minimise the possibility of further hybridisation of wild horses with domestic ones.

keywords

Przewalski's horse, Chernobyl Exclusion Zone, microsatellites, genetic structure.

references

Belkhir, K., P. Borsa, L. Chikhi, N. Raufaste, F. Bonhomme. 2004. GENETIX4. 05, logiciel sous Windows TM pour la genetiquedes populations. Laboratoire genome, populations, interactions, CNRS UMR, 5000: 1996–2004.
Bowling, A. T., W. Zimmermann, O. Ryder, C. Penado, S. Peto, L. Chemnick, N. Yasinetskaya, T. Zharkikh. 2003. Genetic variation in Przewalski’s horses, with special focus on the last wild caught mare, 231 Orlitza III. Cytogenetic and Genome Research, 102 (1–4): 226–234. https://doi.org/10.1159/000075754
Breen, M., P. Downs, Z. Irvin, K. Bell. 1994. An equine tetranucleotide repeat: microsatellite MPZOOB. Animal Genetics, 25: 124.
Breen, M, P. Downs, Z. Irvin, K. Bell. 2009a. An equine tetranucleotide repeat: microsatellite MPZ001. Animal Genetics, 25 (2): 123–123. https://doi.org/10.1111/j.1365-2052.1994.tb00096.x
Breen, M., P. Downs, Z. Irvin, K. Bell. 2009b. Intrageneric amplification of horse microsatellite markers with emphasis on the Przewalski’s horse (E. przewalskii). Animal Genetics, 25 (6): 401–405. https://doi.org/10.1111/j.1365-2052.1994.tb00530.x
Brookfield, J. F. Y. 1996. A simple new method for estimating null allele frequency from heterozygote deficiency. Molecular Ecology, 5 (3): 453–455. https://doi.org/10.1111/j.1365-294X.1996.tb00336.x
Chakraborty, R., M. D. Andrade, S. P. Daiger, B. Budowle. 1992. Apparent heterozygote deficiencies observed in DNA typing data and their implications in forensic applications. Annals of Human Genetics, 56 (1): 45–57. https://doi.org/10.1111/j.1469-1809.1992.tb01128.x
Cornuet, J. M., G. Luikart. 1996. Description and Power Analysis of Two Tests for Detecting Recent Population Bottlenecks From Allele Frequency Data. Genetics, 144 (4): 2001–2014. https://doi.org/10.1093/genetics/144.4.2001
Earl, D. A., B. M. vonHoldt. 2012. STRUCTURE HARVESTER: a website and program for visualizing STRUCTURE output and implementing the Evanno method. Conservation Genetics Resources, 4 (2): 359–361. https://doi.org/10.1007/s12686-011-9548-7
Excoffier, L., H. E. L. Lischer. 2010. Arlequin suite ver 3.5: a new series of programs to perform population genetics analyses under Linux and Windows. Molecular Ecology Resources, 10 (3): 564–567. https://doi.org/10.1111/j.1755-0998.2010.02847.x
Falush, D., M. Stephens, J. K. Pritchard. 2003. Inference of population structure using multilocus genotype data: linked loci and correlated allele frequencies. Genetics, 164 (4): 1567–1587. https://doi.org/10.1093/genetics/164.4.1567
Fauna: Program. 1998. «Fauna» of the Chornobyl Nuclear Power-Plant Exclusion and Absolute Resettlement Zones. Ministry of Extraordinary Situations of the Ukraine Pres, Kyiv.
Goudet, J. 1995. FSTAT (Version 1.2): A Computer Program to Calculate F-Statistics. Journal of Heredity, 86 (6): 485–486. https://doi.org/10.1093/oxfordjournals.jhered.a111627
Hammer, O., D. A. T. Harper, P. D. Ryan. 2001. PAST: Paleontological Statistics Software Package for Education and Data Analysis. Palaeontologia Electronica, 4 (1): 9.
Hoglund, J. 2009. Evolutionary Conservation Genetics. Oxford University Press. https://doi.org/10.1093/acprof:oso/9780199214211.001.0001
Kheidorova, E. E., M. E. Nikiforov, K. V. Homel, A. V. Shpak, V. V. Shakun, V. Ch. Dombrovski, M. G. Shkvyrya. 2020. Analysis of D-loop mitochondrial marker polymorphism of Przewalsky horses Equus caballus przewalskii Poljakov, 1881 and proposals for the species conservation in Belarus. Proceedings of the National Academy of Sciences of Belarus. Biological series, 65 (3): 275–282. https://doi.org/10.29235/1029-8940-2020-65-3-275-282
Kopelman, N. M., J. Mayzel, M. Jakobsson, N. A. Rosenberg, I. Mayrose. 2015. Clumpak: a program for identifying clustering modes and packaging population structure inferences across K. Molecular Ecology Resources, 15 (5): 1179–1191. https://doi.org/10.1111/1755-0998.12387
Peakall, R., P. E. Smouse. 2012. GenAlEx 6.5: genetic analysis in Excel. Population genetic software for teaching and research — an update. Bioinformatics, 28 (19): 2537–2539. https://doi.org/10.1093/bioinformatics/bts460
Peakall, R., P. E. Smouse. 2006. genalex 6: genetic analysis in Excel. Population genetic software for teaching and research. Molecular Ecology Notes, 6 (1): 288–295. https://doi.org/10.1111/j.1471-8286.2005.01155.x
Pritchard, J. K., M. Stephens, P. Donnelly. 2000. Inference of population structure using multilocus genotype data. Genetics, 155: 945–959. https://doi.org/10.1093/genetics/155.2.945
Raymond, M., F. Rousset. 1995. GENEPOP (Version 1.2): Population Genetics Software for Exact Tests and Ecumenicism. Journal of Heredity, 86 (3): 248–249. https://doi.org/10.1093/oxfordjournals.jhered.a111573
Rousset, F. 2008. genepop’007: a complete re-implementation of the genepop software for Windows and Linux. Molecular Ecology Resources, 8 (1): 103–106. https://doi.org/10.1111/j.1471-8286.2007.01931.x
Selkoe, K. A., R. J. Toonen. 2006. Microsatellites for ecologists: a practical guide to using and evaluating microsatellite markers. Ecology Letters, 9 (5): 615–629. https://doi.org/10.1111/j.1461-0248.2006.00889.x
Slivinska, K., N. Yasynetska, D. Klich. 2020. Przewalski`s Wild Horses and Their 18th Years Management in the Chornobyl Exclusion Zone, Ukraine. Proc. International Symposium Ecology 2017, Ercyes University: 90–98.
Wilkinson, G. S., A. M. Chapman. 1991. Length and sequence variation in evening bat D-loop mtDNA. Genetics, 128 (3): 607–617. https://doi.org/10.1093/genetics/128.3.607