Revision and analysis of the chromosome variability in the speciose genus Akodon (Rodentia, Sigmodontinae), including new data from Argentina.

CAROLINA ALICIA LABARONI; PAEZ COLL MAIRHOFER, V.A; AGUSTINA A. OJEDA; AGUSTINA NOVILLO; TETA PABLO; JAYAT PABLO; OJEDA RICARDO ALBERTO; LEANDRO M. BUSCHIAZZO; EUGENIO N. CÁLCENA; ALEJANDRO BOLZAN; CECILIA LANZONE

ANAIS DA ACADEMIA BRASILEIRA DE CIENCIAS.

ACAD BRASILEIRA DE CIENCIAS

Lugar: Rio de Janeiro; Año: 2020

0001-3765

Rodentia has a high species number and chromosomal variability. The South Americangenus Akodon is one of the most speciose muroids, with more than 40 species included inseveral species groups. Here, we characterize cytogenetically specimens of Akodon fromcentral-western Argentina. Subsequently, we reviewed and analyzed the cytogenetic datafor this genus, build a phylogeny and mapped chromosome changes to interpret itsevolution. Specimens of A. dolores from central-western Argentina have 2n=42-44/FNa=44(46, 48) due to a Robertsonian rearrangement. Our data expand the distribution rangeknown for this polymorphism and confirm its geographic structure. Other specimens had2n=40/FNa=40, representing populations of A. oenos, A. polopi, and A. spegazzinii. Allkaryotypes have a low amount of heterochromatin, concentrated in centromeres and sexchromosomes, as in other rodents. The complement with 2n=40/FNa=40 is the mostfrequent in Akodon and is shared by most species in some groups. Chromosome numbersare very diverse. The FNa shows less variability; FNa=42 was recovered as ancestral,excluding A. mimus, which was connected at the base of the Akodon tree and has FNa=44.This indicates a complex chromosome evolution in Akodon, and suggests that reductionsand increases in the 2n and FNa evolved independently in some lineages.