{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,1]],"date-time":"2026-08-01T09:27:03Z","timestamp":1785576423831,"version":"3.56.0"},"reference-count":40,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2022,1,25]],"date-time":"2022-01-25T00:00:00Z","timestamp":1643068800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100002261","name":"Russian Foundation for Basic Research","doi-asserted-by":"publisher","award":["19-04-00759"],"award-info":[{"award-number":["19-04-00759"]}],"id":[{"id":"10.13039\/501100002261","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012190","name":"Ministry of Science and Higher Education of the Russian Federation","doi-asserted-by":"publisher","award":["121031800061-7"],"award-info":[{"award-number":["121031800061-7"]}],"id":[{"id":"10.13039\/501100012190","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100012190","name":"Ministry of Science and Higher Education of the Russian Federation","doi-asserted-by":"publisher","award":["\u0410\u0410\u0410\u0410-\u041019-119020790133-6"],"award-info":[{"award-number":["\u0410\u0410\u0410\u0410-\u041019-119020790133-6"]}],"id":[{"id":"10.13039\/501100012190","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Insects"],"abstract":"<jats:p>This study investigated the relationship between two subspecies of the Citellophilus tesquorum flea, C. t. altaicus and C. t. sungaris, which are vectors of the bacterium Yersinia pestis that causes human plague across the vast territories of the Palearctic. Adult fleas were collected from 16 localities and 11 populations in 2019 and 2020. Specimens were morphologically verified for subspecies status and analysed for mitochondrial cytochrome c oxidase subunit I (COI) DNA, nuclear ribosomal cluster internal transcribed spacer 1 (ITS1) and ITS2, and Wolbachia-infection status. Our results demonstrated a genetic difference between C. t. altaicus and C. t. sungaris. According to mitochondrial data, the genetic distance between clades of C. t. altaicus and C. t. sungaris was comparable with the species divergence of the genus Callopsylla, which is closely related to Citellophilus. All studied populations of C. t. altaicus were Wolbachia-infected, whereas all studied populations of C. t. sungaris were symbiont-free. Data for ITS1 and ITS2 had much lower phylogenetic signals than mitochondrial data; however, diagnostic substitutions for C. t. altaicus and C. t. sungaris delimitation were also revealed. Analysis of a hardly accessible report on cross experiments allowed us to conclude the partial postzygotic isolation between these subspecies. Taken together, the molecular-genetic, geographical, morphological, and reproductive isolation findings verified that C. t. altaicus and C. t. sungaris subspecies could be considered as different species.<\/jats:p>","DOI":"10.3390\/insects13020126","type":"journal-article","created":{"date-parts":[[2022,1,25]],"date-time":"2022-01-25T20:40:18Z","timestamp":1643143218000},"page":"126","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Genetic Evidence of an Isolation Barrier between Flea Subspecies of Citellophilus tesquorum (Wagner, 1898) (Siphonaptera: Ceratophyllidae)"],"prefix":"10.3390","volume":"13","author":[{"given":"Yury","family":"Ilinsky","sequence":"first","affiliation":[{"name":"Laboratory of Molecular Genetics of Insects, Institute of Cytology and Genetics SB RAS, 630090 Novosibirsk, Russia"},{"name":"Center for Mitochondrial Functional Genomics, Immanuel Kant Baltic Federal University, 236041 Kaliningrad, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7030-4988","authenticated-orcid":false,"given":"Vasilina","family":"Lapshina","sequence":"additional","affiliation":[{"name":"Laboratory of Molecular Genetics of Insects, Institute of Cytology and Genetics SB RAS, 630090 Novosibirsk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dmitry","family":"Verzhutsky","sequence":"additional","affiliation":[{"name":"Irkutsk Antiplague Institute, 664047 Irkutsk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yulia","family":"Fedorova","sequence":"additional","affiliation":[{"name":"Laboratory of Molecular Genetics of Insects, Institute of Cytology and Genetics SB RAS, 630090 Novosibirsk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sergey","family":"Medvedev","sequence":"additional","affiliation":[{"name":"Parasitology Department, Zoological Institute RAS, 199034 Saint Petersburg, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,1,25]]},"reference":[{"key":"ref_1","unstructured":"Bisby, F.A., Ruggiero, M.A., Wilson, K.L., Cachuela-Palacio, M., Kimani, S.W., Roskov, Y.R., Soulier-Perkins, A., and van Hertum, J. 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