Superspecies complex Cricetulus barabensis sensu lato: Karyotype divergence and interrelation in natural contact zones

详细信息    查看全文

• 作者：N. S. Poplavskaya (1)
  V. S. Lebedev (2)
  A. A. Bannikova (3)
  I. G. Meshcherskii (1)
  A. V. Surov (1)
  
• 刊名：Biology Bulletin Reviews
• 出版年：2013
• 出版时间：January 2013
• 年：2013
• 卷：3
• 期：1
• 页码：73-83
• 全文大小：264KB
• 参考文献：1. Argyropulo, A.I., Die Gattungen und Arten der Hamster (Cricetinae, Murray, 1866) der Pal?arktik, / Zeitschrift für Z?ugetierkunde, 1933, vol. 8, no. 3, pp. 129-49.
  2. Baker, R.J. and Bradley, R.D., Speciation in Mammals and the Genetic Species Concept, / J. Mammal., 2006, vol. 87, no. 4, pp. 643-62. CrossRef
  3. Baverstock, P.R., Gelder, M., and Jahnke, A., Chromosome Evolution in Australian / Rattus-G-Banding and Hybrid Meiosis, / Genetics, 1983, vol. 60, pp. 93-03.
  4. Baverstock, P.R., Adams, M., and Watts, C.H.S., Biochemical Differentiation among Karyotypic Forms of Australian / Rattus, / Genetics, 1986, vol. 71, pp. 11-2.
  5. Bermingham, E. and Alvise, J.C., Molecular Zoogeography of Freshwater Fishes in the Southeastern United States, / Genetics, 1986, vol. 113, pp. 6624-628.
  6. Bozikova, E., Munclinger, P., Teeter, K.C., Tucker, P.K., Macholan, M., and Pialek, J., Mitochondrial DNA in the Hybrid Zone between / Mus musculus musculus and / Mus musculus domesticus: A Comparison of Two Transects, / Biol. J. Linnean Soc., 2005, vol. 84, pp. 363-78. CrossRef
  7. Bradley, R.D. and Baker, R.J., A Test of the Genetic Species Concept: Cytochrome- / b Sequences and Mammals, / J. Mammal., 2001, vol. 82, no. 4, pp. 960-73. CrossRef
  8. Britton-Davidian, J., Felclair, F., Lopez, J., Alibert, P., and Boursot, P., Postzygotic Isolation Between the Two European Subspecies of the House Mouse: Estimates from Fertility Patterns in Wild and Laboratory-Bred Hybrids, / Biol. J. Linnean Soc., 2005, vol. 84, pp. 379-93. CrossRef
  9. Brunner, H., Lugon-Moulin, N., and Hausser, J., Alps, Genes, and Chromosomes: Their Role in the Formation of Species in the / Sorex araneus Group (Mammalia, Insectivora), As Inferred from Two Hybrid Zones, / Cytogenet. Genome Res., 2002, vol. 96, pp. 85-6. CrossRef
  10. Bulatova, N.Sh., Golenishchev, F.N., Koval’skaya, Yu.M., Emel’yanova, L.G., Bystrakova, N.V., Pavlova, S.V., Nadzhafova, R.S., and Lavrenchenko, L.A., Cytogenetic Study of the Parapatric Contact Zone between Two 46-Chromosomal Forms of the Common Vole in European Russia, / Russ. J. Genet., 2010, vol. 46, no. 4, pp. 443-48. CrossRef
  11. Cherepanova, E.V., Postzygotic Isolation of Hamsters / Phodopus campbelli and / Phodopus sungorus and Their Cytogenetic Characteristics, / Extended Abstract of Cand. Sci. (Biol.) Dissertation, Moscow: IPEE RAN, 2001.
  12. Cothran, E.G., Zimmerman, E.G., and Nadler, C.F., Genic Differentiation and Evolution in the Ground Squirrel Subgenus / Ictidomys (Genus / Spermophilus), / J. Mammal., 1977, vol. 58, pp. 610-22. CrossRef
  13. Cothran, E.G., Morphologic Relationships of the Hybridizing Ground Squirrels / Spermophilus mexicanus and / S. tridecemlineatus, / J. Mammalogy, 1983, vol. 64, pp. 591-02. CrossRef
  14. Cothran, E.G. and Honeycutt, R.L., Chromosomal Differentiation of Hybridizing Ground Squirrels ( / Spermophilus mexicanus and / S. tridecemlineatus), / J. Mammalogy, 1984, vol. 65, pp. 118-22. CrossRef
  15. Coyne, J.A. and Orr, H.A., The Evolutionary Genetics of Speciation, / Philos. Transact. Roy. Soc., 1998, vol. 353, pp. 287-05. CrossRef
  16. Currat, M. and Excoffier, L., Strong Reproductive Isolation between Humans and Neanderthals Inferred from Observed Patterns of Introgression, / Proc. Natl. Acad. Sci. USA, 2011, vol. 108, pp. 15129-5134. CrossRef
  17. Dawson, W.D., Postnatal Development in / Peromyscus maniculalus-polionotus Hybrids. I. Developmental Landmarks and Litter Mortality, / Ohio J. Sci., 1966, vol. 66, p. 518.
  18. Dobzhansky, T., / Genetics and the Origin of Species, New York: Columbia Univ. Press, 1937.
  19. Excoffier, L., Laval, G., and Schneider, S., Arlequin ver. 3.0: An Integrated Software Package for Population Genetics Data Analysis, / Evolutionary Bioinformatics Online, 2005, vol. 1, pp. 47-0.
  20. Formozov, A.N., Mammals of Northern Mongolia According to the Specimens Collected during the Expedition of 1926, in / Mater. komissii po issledovaniyu Mongol’skoi, Tannu-Tuvinskoi Narodnoi Respubliki i Buryat-Mongol’skoi ASSR (Transactions of the Commission for Studying Mongolian Republic, Tannu-Tuva People’s Republic, and Buryat-Mongol Autonomous Soviet Socialist Republic), 1929, vol. 3.
  21. Golenischev, F.N., Meyer, M.N., and Bulatova, N.Sh., The Hybrid Zone between Two Karyomorphs of / Microtus arvalis (Rodentia, Arvicolidae), / Proc. Zool. Inst. RAS, 2001, vol. 289, pp. 89-4.
  22. Good, J.M. and Sullivan, J., Phylogeography of the Redtailed Chipmunk ( / Tamias ruficaudus), a Northern Rocky Mountain Endemic, / Mol. Ecol., 2001, vol. 10, pp. 2683-695. CrossRef
  23. Gromov, I.M. and Erbaeva, M.A., Mammals of Russia and Adjacent Territories, in / Zaitseobraznye i gryzuny (Lagomorphs and Rodents), St. Petersburg: ZIN RAN, 1995.
  24. Hafner, D.J., Speciation and Persistence of a Contact Zone in Mojave Desert Ground Squirrels, Subgenus / Xerospermophilus, / J. Mammalogy, 1992, vol. 73, pp. 770-78. CrossRef
  25. Harrison, R.G., Bogdanowicz, S.M., Hoffmann, R.S., Yensen, E., and Sherman, P.W., Phylogeny and Evolutionary History of the Ground Squirrels (Rodentia: Marmotinae), / J. Mammal. Evol., 2003, vol. 10, pp. 249-76. CrossRef
  26. Hellborg, L. and Ellegren, H., Y Chromosome Conserved Anchored Tagged Sequences (YCATS) for the Analysis of Mammalian Male-Specific DNA, / Mol. Ecol., 2003, vol. 12, no. 1, pp. 283-91. CrossRef
  27. Hird, S. and Sullivan, J., Assessment of Gene Flow across a Hybrid Zone in Red-Tailed Chipmunks ( / Tamias ruficaudus), / Mol. Ecol., 2009, vol. 18, pp. 3097-109. CrossRef
  28. Karaseva, E.V., The Impact of Plowing Virgin Lands on the Lifestyle and Spatial Distribution of Rodents in Northern Kazakhstan, / Zool. Zh., 1961, vol. 40, no. 5, pp. 768-73.
  29. Kartavtseva, I.V., Problems of Karyosystematics and Phylogeny of Palaearctic Rodents, / Extended Abstract of Doctoral (Biol.) Dissertation, Vladivostok: Biol.-Pochv. Inst. DVO RAN, 2002.
  30. Korablev, V.P., Kirilyuk, V.E., and Pavlenko, M.V., Refining the Boundary of the Distribution of the Transbaikal Hamster ( / Cricetulus pseudogeiseus) in Transbaikalia, / Biologiin Khyreelen Erdem Shinzhilgeenii Byteel (Proc. Inst. Zool.), 2003, no. 24, pp. 85-7.
  31. Korablev, V.P., Pavlenko, M.V., Kirilyuk, V.E., and Bazhenov, Yu.A., Distribution of Hamsters of Different Chromosomal Forms of the Superspecies / Cricetulus barabensis in Transbaikalia, in / Prirodookhrannoe sotrudnichestvo v global’nykh ekologicheskikh regionakh: Rossiya-Kitai-Mongoliya: sbornik nauchnykh materialov (Nature Conservation Cooperation in Global Environmental Regions: Russia-China-Mongolia: A Collection of Scientific Documents), Chita: Express Izd., 2010, pp. 131-33.
  32. Kral, B., Radjabli, S.L., Grafodatsky, A.S., and Orlov, V.N., Comparison of Karyotypes, G-Bands and NORs in Three / Cricetulus spp. (Rodentia, Cricetidae), / Folia Zool., 1984, vol. 33, no. 1, pp. 85-6.
  33. Lavrenchenko, L.A., Kotenkova, E.V., and Bulatova, N.Sh., Experimental Hybridization of House Mice, in / Domovaya mysh-/em> (House Mouse), Kotenkova, E.V. and Bulatova, N.Sh., Eds., Moscow: Nauka, 1994, pp. 93-09.
  34. Lebedev, V.S. and Koval’skaya, Yu.M., New Data on the Distribution of Chromosomal Forms of the Superspecies / Cricetulus barabensis (Rodentia, Muridae) in the Selenga River Basin, in / Filogeniya, sistematika i paleontologiya melkikh mlekopitayushchikh (Phylogeny, Systematics and Paleontology of Small Mammals), Aver’yanov, A.O. and Abramson, N.I., Eds., St. Petersburg: ZIN RAN, 2003, pp. 119-20.
  35. Lebedev, V.S. and Lisovskii, A.A., Geographic Variation of Metric Traits of the Skull and the Taxonomic Structure of Hamsters of the / Cricetulus barabensis Group (Rodentia, Cricetidae), / Zool. Zh., 2008, vol. 87, no. 3, pp. 361-74.
  36. Lebedev, V.S., Bannikova, A.A., Tesakov, A.S., and Abramson, N.I., Molecular Phylogeny of the Genus / Alticola (Cricetidae, Rodentia) as Inferred from the Sequence of the Cytochrome / b Gene, / Zoologica scripta, 2007a, vol. 36, pp. 547-63. CrossRef
  37. Lebedev, V.S., Surov, A.V., Korablev, V.P., and Bannikova, A.A., Intraspecific Systematics and Phylogeography of Hamsters of the Superspecies / Cricetulus barabensis, in / Molekulyarno-geneticheskie osnovy sokhraneniya raznoobraziya mlekopitayushchikh Golarktiki. Mater. Mezhdunar. Konf. 26-0 noyabrya 2007 g., Chernogolovka (Molecular and Genetic Basis of Conservation of the Diversity of Mammals of the Holarctic: Proc. Int. Conf., November 26-0, 2007, Chernogolovka), Moscow: Tovar. Nauch. Izd. KMK, 2007b, pp. 152-55.
  38. Lebedev, V.S., Bannikova, A.A., and Surov, A.V., Systematics of Striped Hamsters ( / Cricetulus barabensis Group) from Morphological and Genetic Viewpoints, in / Cricetinae. Internazionales Ehrensymposium Im Gedeken an Rolf Gattermann. Abhandlungen der Sachsischen Akademie der Wissenchaften Zu, Leipzig: Mathematischnaturwissenschaftliche Klasse, Herausgegeben von Peschke E., Moritz G. Band, 2008, vol. 64, no. 5, pp. 69-6.
  39. Lugon-Moulin, N. and Hausser, J., Phylogeographical Structure, Postglacial Recolonization and Barriers to Gene Flow in the Distinctive Valais Chromosome Race of the Common Shrew ( / Sorex sraneus), / Mol. Ecol., 2002, vol. 11, pp. 785-94. CrossRef
  40. Lundrigan, B.L., Jansa, S.A., and Tucker, P.K., Phylogenetic Relationships in the Genus / Mus, Based on Paternally, Maternally, and Bi-Parentally Inherited Characters, / Syst. Biol., 2002, vol. 51, pp. 410-31. CrossRef
  41. Macholan, M., Munclinger, P., Sugerkova, M., Dufkova, P., Bimova, B., Bozikova, E., Zima, J., and Pialek, J., Genetic Analysis of Autosomal and X-Linked Markers across a Mouse Hybrid Zone, / Evolution, 2007, vol. 61, pp. 746-71. CrossRef
  42. Malygin, V.M., Startsev, N.V., and Zima, Ya., Karyotypes and Distribution of Hamsters of the / barabensis Group (Rodentia, Cricetidae), / Vestn. Mosk. Univ., Ser. 16. Biol., 1992, no. 2, pp. 32-9.
  43. Matthey, R., Chromosomes de Muridae, II, / Experientia (Basel), 1952, vol. 8, pp. 389-90. CrossRef
  44. Matthey, R., Formules Chromosomiques de Muridae et Spalacidae, la Question du Polymorphisme Chromosomique Chez les Mammiferes, / Rev. Suisse Zool., 1959, vol. 66, pp. 175-09.
  45. Matthey, R., Chromosomes, Heterochromosomes et Cytology Comparee des Cricetinae Palearctiques (Rodentia), / Caryologia, 1960, vol. 13, pp. 199-23.
  46. Mayden, R.L., A Hierarchy of Species Concepts: The Denouement in the Saga of the Species Problem, in / Species: The Units of Biodiversity, Claridge, M.F., Dawah, H.A., and Wilson, M.R., Eds., London: Chapman and Hall, 1997, pp. 381-24.
  47. Mayr, E., / Systematics and the Origin of Species, from the Viewpoint of a Zoologist, New York: Columbia Univ. Press, 1942.
  48. Morin, P.A., Moore, J.J., Chakraborty, R., Goodall, L.J.J., and Woodruff, D.S., Kin Selection, Social Structure, Gene Flow, and the Evolution of Chimpanzees, / Science, 1994, vol. 265, pp. 1193-201. CrossRef
  49. Musser, G.G. and Carleton, M.D., / Mammal Species of the World. A Taxonomic and Geographic Reference, 3rd ed., Wilson, D.E. and Reeder, D.M., Eds., Baltimore: Johns Hopkins Univ. Press, 2005.
  50. Nekipelov, N.V., Transbaikal Hamsters and Some Ecological Features of the Cricetinae Subfamily, / Izv. Irkutsk. Gos. Nauch.-Issled. Protivochumn. Inst. Sibiri i DV, 1960, vol. 23, pp. 147-63.
  51. Neumann, K., Neumann, S., Gattermann, R., Michaux, J., Lebedev, V., Yigit, N., Colak, E., Ivanova, N., Poltoraus, A., Surov, A., Markov, G., and Maak, S., Molecular Phylogeny of the Cricetinae Subfamily Based on the Mitochondrial Cytochrome / b and 12S rRNA Genes and the Nuclear / VWF Gene, / Mol. Phylogenet. Evol., 2006, vol. 39, no. 1, pp. 135-48. CrossRef
  52. Ohdachi, S.D., Dokuchaev, N.E., Hasegawa, M., and Masuda, R., Intraspecific Phylogeny and Geographical Variation of Six Species of Northeastern Asiatic / Sorex Shrews Based on the Mitochondrial Cytochrome / b Sequences, / Mol. Ecol., 2001, vol. 10, pp. 2199-213. CrossRef
  53. Orlov, V.N. and Iskhakova, E.N., Taxonomy of the Superspecies / Cricetulus barabensis (Rodentia, Cricetidae), / Zool. Zh., 1975, vol. 54, no. 4, pp. 597-04.
  54. Orlov, V.N. and Malygin, V.M., A New Species of Hamsters- / Cricetulus sokolovi sp. n. (Rodentia, Cricetidae) from the Mongolian People’s Republic, / Zool. Zh., 1988, vol. 67, no. 2, pp. 304-08.
  55. Pavlinov, I.Ya., The Species Problem in Biology-Another Point of View, in / Vid i vidoobrazovanie. Analiz novykh vzglyadov i tendentsii (Tr. ZIN RAN, Prilozhenie no. 1) (Species and Speciation. Views and Analysis of New Ideas and Trends. Transaction of the Zoological Institute of RAS, Annex no. 1), Alimov, A.F. and Stepan’yants, S.D., Eds., 2009, pp. 259-71.
  56. Pavlinov, I.Ya., Yakhontov, E.L., and Agadzhanyan, A.K., / Mlekopitayushchie Evrazii. I. Rodentia: sistematikogeograficheskii spravochnik. (Issledovaniya po faune) (Mammals of Eurasia. I. Rodentia: Taxonomic and Geographic Reference. (Faunal Studies)), Moscow: Mosk. Gos. Univ., 1995.
  57. Petit, R.J. and Excoffier, L., Gene Flow and Species Delimitation, / Trends Ecol. Evol., 2009, vol. 24, pp. 386-93. CrossRef
  58. Poplavskaya, N.S., Lebedev, V.S., Bannikova, A.A., Malygin, V.M., and Surov, A.V., Interpopulation Karyotype Variability in Hamster of the “barabensis-Group (Cricetidae, Rodentia) from Central Mongolia and Possible Reasons of Its Origin, / Dokl. Biol. Sci., 2011, vol. 439, pp. 225-27. CrossRef
  59. Raufaste, N., Orth, A., Belkhir, K., Senet, D., Smadja, C., Baird, S.J.E., Bonhomme, F., Dod, B., and Boursot, P., Inferences of Selection and Migration in the Danish House Mouse Hybrid Zone, / Biol. J. Linn. Soc. Lond., 2005, vol. 84, pp. 593-16. CrossRef
  60. Rowe, K.C., Aplin, K.P., Baverstock, P.R., and Moritz, C., Recent and Rapid Speciation with Limited Morphological Disparity in the Genus / Rattus, / Syst. Biol., 2011, vol. 60, no. 2, pp. 188-03. CrossRef
  61. Sambrook, J., Fritsch, E.F., and Maniatis, T., / Molecular Cloning: A Laboratory Manual, New York: Cold Spring Harbor Lab. Press, 1989.
  62. Satoh, Y., Mano, T., Tsuruga, H., Masuda, R., Matsuhashi, T., Onuma, M., Suzuki, M., and Ohtaishi, N., Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) Method for mt-DNA Typing in Hokkaido Brown Bear ( / Ursus arctos yesoensis), / Jpn. J. Vet. Res., 2003, vol. 50, no. 4, pp. 195-99.
  63. Schneider, S. and Excoffier, L., Estimation of Demographic Parameters from the Distribution of Pairwise Differences When the Mutation Rates Vary among Sites: Application to Human Mitochondrial DNA, / Genetics, 1999, vol. 152, pp. 1079-089.
  64. Shkilev, V.V., The Abundance of White-Naped Hamsters and the Causes of Its Changes in Primorie (Far East), / Izv. Irkutsk. Gos. Nauch.-Issled. Protivochumn. Inst. Sibiri i DV, 1966, vol. 26, pp. 206-13.
  65. Slatkin, M. and Hudson, R.R., Pairwise Comparisons of Mitochondrial DNA Sequences in Stable and Exponentially Growing Populations, / Genetics, 1991, vol. 129, pp. 555-62.
  66. Smith, D.R., Palopoli, M.F., Taylor, B.R., Garnery, L., Cornuet, J.M., Solignac, M., and Brown, W.M., Geographical Overlap of Two Mitochondrial Genomes in Spanish Honeybees ( / Apis mellifera iberica), / J. Heredity, 1991, vol. 82, pp. 96-00.
  67. Tajima, F., Statistical Method for Testing the Neutral Mutation Hypothesis by DNA Polymorphism, / Genetics, 1989, vol. 123, pp. 585-95.
  68. Teeter, K.C., Thibodeau, L.M., Gompert, Z., Buerkle, C.A., Nachman, M.W., and Tucker, P.K., The Variable Genomic Architecture of Isolation between Hybridizing Species of House Mice, / Evolution, 2010, vol. 64, pp. 472-85. CrossRef
  69. Vinogradova (Poplavskaya), N.S., Lebedev, V.S., and Surov, A.V., Hybridization Analysis of Hamsters of the / Cricetulus barabensis s.l. Group, in / Mater. Konf. “Aktual’nye problemy ekologii i evolyutsii v issledovaniyakh molodykh uchenykh-/em> (Proc. Conf. “Topical Problems of Ecology and Evolution in the Studies of Young Scientists-, 2006, pp. 83-6.
  70. Vrana, P.B., Fossella, J.A., Matteson, P., del Rio, T., O’Neill, M.J., and Tilghman, S.M., Genetic and Epigenetic Incompatibilities Underlie Hybrid Dysgenesis in Peromyscus, / Nat. Genet., 2000, vol. 25, no. 1, pp. 120-24. CrossRef
  71. Wang, F., Subspecific Classification of the Black Stripe Hamsters ( / Cricetulus barabensis) in China, with Description of a New Subspecies, / Acta Zootaxonom. Sin., 1980, vol. 5, no. 3, pp. 315-19.
  72. Won, Y.J. and Hey, J., Divergence Population Genetics of Chimpanzees, / Mol. Biol. Evol., 2005, vol. 22, pp. 297-07. CrossRef
  73. Yannic, G., Basset, P., and Hausser, J., A Hybrid Zone with Coincident Clines for Autosomal and Sex-Specific Markers in the / Sorex araneus Group, / J. Evol. Biol., 2008, vol. 21, no. 3, pp. 658-67. CrossRef
  74. Yudin, B.S., Galkina, L.I., and Potapkina, A.F., / Mlekopitayushchie Altae-Sayanskoi gornoi strany (Mammals of the Altai-Sayan Mountain Country), Novosibirsk: Nauka, 1979.
  75. Zhang, Y., Jin, S., Quan, G., Li, S., Ye, Z., Wang, F., and Zhang, M., / Distribution of Mammalian Species in China, Beijing: China Forestry Publishing House, 1997.
  76. Zorenko, T.A. and Malygin, V.M., The Action of Ethological Mechanisms of Reproductive Isolation in Hybridization of Three Species of Common Voles of the / arvalis Group (Microtus, Rodentia), / Zool. Zh., 1984, vol. 63, no. 7, pp. 1072-082.
  
• 作者单位：N. S. Poplavskaya (1)
  V. S. Lebedev (2)
  A. A. Bannikova (3)
  I. G. Meshcherskii (1)
  A. V. Surov (1)
  
  1. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Leninskii pr. 33, Moscow, 119071, Russia
  2. Zoological Museum, Moscow State University, Bol’shaya Nikitskaya 6, Moscow, 125009, Russia
  3. Department of Biology, Moscow State University, Moscow, 119991, Russia
  

文摘

Three different chromosomal forms of striped hamsters that belong to the superspecies complex Cricetulus barabensis sensu lato (Cricetidae, Rodentia), namely, “barabensis- “pseudogeiseus- and “griseus- were studied to determine their relationships based on different biological and genetic species concepts and using the morphological, karyomorphs, molecular, and hybridization data. The results of craniometry suggest that differences between these karyotypes are rather of subspecies level. Cytogenetic differences also proved to be insignificant and correspond to the level of chromosomal races within a single species. An analysis of cytochrome b mitochondrial gene (cytb) differences of about 2.3-.1% between the forms studied, which suggest intraspecific distinctions or those between allied species. Hybridization experiments, which produced various litters from mating between three karyomorphs, also confirmed both male and female fertility. In nature, there are several zones where contact is possible between the “barabensis-and “pseudogeiseus-karyomorphs. In one of these zones, in Central Mongolia, atypical karyotypes were found in two male specimens using chromosomal analysis. Taking into account the chromosome number and shape, this karyotype could be attributed to a hybrid between the second and subsequent generations. However, typing the cytb gene and intron localized to Y chromosome (DBY1) did not reveal any traces of recent or ancient hybridization. In another zone, in South Buryatia, where the contact could be expected between the karyomorphs studied, the “barabensis-and “pseudogeiseus-populations are separated by the Chikoi River and the distance between them does not exceed 5 km. Nevertheless, neither karyological nor molecular analysis detected any hamsters with nonstandard karyotypes or any traces of gene flow. An analysis of the entire cytb nucleotide sequence, as well as the Tajima’s test, the distribution of pairwise differences, and the level of nucleotide diversity suggest that both contact zones have formed long ago; the absence of gene flow cannot be explained by their recent formation. Thus, the evolutionary formation of each of the three karyomorphs that were the subject of our study appears to be independent.