title: Mitochondrial and chromosomal insights into karyotypic evolution of the pygmy mouse, Mus minutoides, in South Africa.
abstract: The African pygmy mouse, Mus minutoides, displays extensive Robertsonian (Rb) diversity. The two extremes of the karyotypic range are found in South Africa, with populations carrying 2n = 34 and 2n = 18. In order to reconstruct the scenario of chromosomal evolution of M. minutoides and test the performance of Rb fusions in resolving fine-scale phylogenetic relationships, we first describe new karyotypes, and then perform phylogenetic analyses by two independent methods, using respectively mitochondrial cytochrome b sequences and chromosomal rearrangements as markers. The molecular and chromosomal phylogenies were in perfect congruence, providing strong confidence both for the tree topology and the chronology of chromosomal rearrangements. The analysis supports a division of South African specimens into two clades showing opposite trends of chromosomal evolution, one containing all specimens with 34 chromosomes (karyotypic stasis) and the other grouping all mice with 18 chromosomes that have further diversified by the fixation of different Rb fusions (extensive karyotypic reshuffling). The results confirm that Rb fusions are by far the predominant rearrangement in M. minutoides but strongly suggest that recurrent whole-arm reciprocal translocations have also shaped this genome.
authors.affiliation: Institut des Sciences de l'Evolution, UMR5554 CNRS/Université Montpellier II, Montpellier, France. frederic.veyrunes@univ-montp2.fr
authors.forename: Frederic
authors.initials: F
authors.lastname: Veyrunes
authors.forename: Josette
authors.initials: J
authors.lastname: Catalan
authors.forename: Caroline
authors.initials: C
authors.lastname: Tatard
authors.forename: Elise
authors.initials: E
authors.lastname: Cellier-Holzem
authors.forename: Johan
authors.initials: J
authors.lastname: Watson
authors.forename: Pascale
authors.initials: P
authors.lastname: Chevret
authors.forename: Terence J
authors.initials: TJ
authors.lastname: Robinson
authors.forename: Janice
authors.initials: J
authors.lastname: Britton-Davidian
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002869:Chromosome Aberrations; D033481:Chromosomes, Mammalian / Q000235:genetics*; D007621:Karyotyping; D051379:Mice / Q000235:genetics*; D008928:Mitochondria / Q000235:genetics*; D010802:Phylogeny; D014178:Translocation, Genetic