Albumin systematics of the extinct mammoth and Tasmanian wolf

Knowledge of the molecular systematics of living species 1–3 has provided a framework, independent of morphology, for evaluating the genetic relationships of living forms. Although amino acids have been found in many animal and plant fossils 4 , genetic information has generally not been obtained from the small amounts of surviving, chemically degraded protein. However, Westbroek et al. 5 have described immunological reactions to material from 60-Myr-old molluscs, and Lowenstein 6,7 has reported the identification by radioimmunoassay (RIA) of species-specific collagen and serum factors in primate and bovine fossils. We report here the use of RIA to detect and characterize albumin in the soft tissues of two recently extinct species, the Siberian mammoth ( Mammuthus primigenius ) and the Tasmanian wolf ( Thylacinus cynocephalus ). Mammoth albumin was found to be very similar to, and immunologically equidistant from, the albumins of the two living species of elephants, Indian ( Elephas maximus ) and African ( Loxodonta africana ). Tasmanian wolf albumin stands in the same relationship to those of the two Australian marsupial dasyurids, Dasyurus and Dasyuroides .