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Strong hybrid viability between two widely divergent chromosomal forms of the pouched mouse
Author(s) -
Maputla N. W.,
Dempster E. R.,
Raman J.,
Ferguson J. W. H.
Publication year - 2011
Publication title -
journal of zoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0952-8369
DOI - 10.1111/j.1469-7998.2011.00825.x
Subject(s) - biology , hybrid , karyotype , taxon , species complex , zoology , crossbreed , evolutionary biology , chromosome , genetics , botany , phylogenetic tree , gene
A large degree of karyotypic diversity in the pouched mouse Saccostomus campestris , ranging from 2 n =28 to 2 n =46, is mostly due to centric fusions. The taxon comprises a complex of cryptic species, of which the 2 n =32 and 2 n =46 karyotypes represent two different species. Crossbreeding pure 2 n =32 and pure 2 n =46 karyotypes up to the F3 hybrid generation yielded F1 hybrids with 39 chromosomes, seven of which were unpaired. Unpaired chromosomes ranged in size from very long to short. We measured the growth rate, testis structure and litter size of these crosses and did not find any indication that the F1, F2 or F3 generations exhibit any degree of hybrid disadvantage or hybrid breakdown. The interpretation of these results is strongly affected by the species concept used, but weakens the conclusions of several other authors that S. campestris in southern Africa comprises a complex of cryptic species.