Systematics of the Microtus savii complex (Rodentia, Cricetidae) via mitochondrial DNA analyses: paraphyly and pattern of sex chromoseme evolution (Articolo in rivista)

Type
Label
  • Systematics of the Microtus savii complex (Rodentia, Cricetidae) via mitochondrial DNA analyses: paraphyly and pattern of sex chromoseme evolution (Articolo in rivista) (literal)
Anno
  • 2008-01-01T00:00:00+01:00 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
  • 10.1016/j.ympev.2007.12.005 (literal)
Alternative label
  • Castiglia R.(1); Annesi F.(1); Aloise G.(2); Amori G. (2008)
    Systematics of the Microtus savii complex (Rodentia, Cricetidae) via mitochondrial DNA analyses: paraphyly and pattern of sex chromoseme evolution
    in Molecular phylogenetics and evolution (Print)
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Castiglia R.(1); Annesi F.(1); Aloise G.(2); Amori G. (literal)
Pagina inizio
  • 1157 (literal)
Pagina fine
  • 1164 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#altreInformazioni
  • ISI WOS KeyWords Plus: GENETIC SPECIES CONCEPT; PHYLOGENETIC-RELATIONSHIPS; COMPARATIVE PHYLOGEOGRAPHY; POSTGLACIAL COLONIZATION; GENUS MICROTUS; VOLE; ARVICOLIDAE; SEQUENCES; MAMMALS; HETEROCHROMATIN (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume
  • 46 (literal)
Rivista
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • (1) Department of Human and Animal Biology, University of Rome ''La Sapienza\", Via A. Borelli 50, 00161 Rome, Italy; (2) Department of Ecology, Universita` della Calabria, Via P. Bucci, s.n., 87036 Rende (CS), Italy (literal)
Titolo
  • Systematics of the Microtus savii complex (Rodentia, Cricetidae) via mitochondrial DNA analyses: paraphyly and pattern of sex chromoseme evolution (literal)
Abstract
  • The genus Microtus underwent a rapid evolutionary radiation that resulted in the extant 59 species distributed throughout the Palaearctic and Nearctic regions. The rapidity of speciation events within the genus is reflected in the widespread low interspecific morphological divergence, with the presence of many sibling species. However, high intraspecific morphological variation of dental and other skull characters has led to the proliferation of subspecific names, causing even more confusing systematics of the genus. Studies on karyotypes and DNA sequences have revealed extensive variation among species. Hence, a genetic approach is essential to delimit species and assess the phylogenetic relationships of the groups. The Italian endemic voles belonging to the Microtus savii complex represent another case of this systematic uncertainty. The taxa of this species complex are slightly different morphologically and have a variable karyotype. The diploid number is 2n = 54, with a constant autosomal set and variation in the shape and size of the sex chromosomes. This chromosomal and morphological polytypism has led to the identification of five taxa. The specific rank of \"savii\" and \"brachycercus\" was suggested by Galleni et al. (1994) and was accepted by Musser and Carleton (2005). These two taxa have different sex chromosomes, \"savii\" with a metacentric X and a small acrocentric Y, \"brachycercus\" with a submetacentric X and a large acrocentric Y. Galleni et al. (1994) studied the fertility of hybrids between these two cytotypes and found that male hybrids were sterile: they did not produce offspring and showed cell degeneration and absence of spermatozoa in the testes. However, female hybrids were fertile and could produce litters with a normal number of pups. For these reasons, the taxon \"brachycercus\" was assigned to a different species, M. brachycercus, restricted to southern Italy (Calabria). All the voles with a metacentric X and small Y were attributed to the nominal species M. savii. They include three subspecies: M. s. savii from north-central Italy, M. s. tolfetanus restricted to a small area in central Italy (not shown) and M. s. nebrodensis from Sicily. Moreover, within M. savii, a third type of X (acrocentric) has been found for a recently described subspecies named M. s. niethammericus. Since no molecular genetic data are available for this M. savii complex, with the exception of five specimens analysed by Jaarola et al. (2004), we analysed sequences of the mtDNA gene for cytochrome-b (cyt-b) in specimens collected throughout the Italian peninsula, including three subspecies of M. savii (M. s. savii, M. s. niethammericus and M. s. nebrodensis) and M. brachycercus. The here presented results of the phylogenetic analyses show that M. savii is a paraphyletic taxon and that the estimated genetic divergence among taxa does not correspond to that of currently recognized species. We also discuss the pattern of sex chromosome evolution, believed to have had a role in the speciation processes in this species complex. (literal)
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