Sheep ideal research subjects, and thus are not a common model organism. They have, however, played an influential role in some fields of science. In particular, the Roslin Institute of Edinburgh, Scotland used sheep for genetics research that produced groundbreaking results. In 1995, two ewes named Megan and Morag were the first mammals cloned from differentiated cells. A year later, a Finnish Dorset sheep named Dolly, dubbed "the world's most famous sheep" in "Scientific American", was the first mammal to be cloned from an adult somatic cell. Following this, Polly and Molly were the first mammals to be simultaneously cloned and
Mammal species included 96 recently extinct. The word "[[:wikt:mammal|mammal]]" is modern, from the scientific name "Mammalia" coined by Carl Linnaeus in 1758, derived from the [[Latin language|Latin]] "[[wikt:mamma#Latin|mamma]]" ("teat, pap"). In an influential 1988 paper, Timothy Rowe defined Mammalia [[Phylogenetics|phylogenetically]] as the [[crown group]] of mammals, the [[clade]] consisting of the [[most recent common ancestor]] of living [[monotreme]]s ([[echidna]]s and [[platypus]]es) and [[theria]]n mammals ([[marsupial]]s and [[placental]]s) and all descendants of that ancestor. Since this ancestor lived in the [[Jurassic]] period, Rowe's definition excludes all animals from the earlier [[Triassic]], despite the fact that Triassic fossils in the [[Haramiyida]] have been