MOLECULAR PHYLOGENY OF RODENTS, WITH SPECIAL EMPHASIS ON MURIDS - EVIDENCE FROM NUCLEAR GENE LCAT

Phylogenetic relationships among 19 extant species of rodents, with sp ecial emphasis on rats, mice, and allied Muroidea, were studied using sequences of the nuclear protein-coding gene LCAT (lecithin:cholestero l acyltransferase), an enzyme of cholesterol metabolism. Analysis of 7 05 base pairs from the exonic regions of LCAT confirmed known grouping s in and around Muroidea. Strong support was found for the families Sc iuridae (squirrel and marmot) and Gliridae (dormice) and for suprafami lial taxa Muroidea and Caviomorpha (guinea pig and allies). Within Mur oidea, the first branching leads to the fossorial mole rats Spalacinae and bamboo rats Rhizomyinae. The other Muroidea appear as a polytomy from which are issued Gerbillinae (gerbils), Murinae (rats and mice), Sigmodontinae (New World cricetids), Cricetinae (hamsters), and Arvico linae (voles). Evidence from LCAT sequences agrees with that from a nu mber of previous molecular and morphological studies, both concerning branching orders inside Muroidea and the bush-like radiation of rodent suprafamilial taxa (caviomorphs, sciurids, glirids, muroids), thus su ggesting that this nuclear gene is an appropriate candidate for addres sing questions of rodents relationships. (C) 1997 Academic Press.