| Functional |
"Adaptive nonshivering thermogenesis (NST) of placental mammals is predominantly mediated by uncoupling protein 1 (UCP1), which resides at high levels in the mitochondrial inner membrane of brown adipose tissue (BAT) (1)." |
10.1126/sciadv.1602878 |
| Methodology & Validation |
"We thus verified this deletion in both African and Asian elephant (Elephas maximus) DNA samples via PCR and Sanger sequencing techniques. PCR was also used to obtain ucp1 sequences from the three-toed brown-throated sloth (B. variegatus), silky anteater (Cyclopes didactylus), bowhead whale (Balaena mysticetus), Grant’s zebra (Equus quagga boehmi), black rhinoceros (Diceros bicornis), and Indian rhinoceros (Rhinoceros unicornis). Specimen information is provided in table S7 (64, 69–71)." |
10.1126/sciadv.1602878 |
| Timing of Loss |
"For example, theearliest proboscideans [59 to 60 million–year–old (Ma) Eritherium(41)] and hyraxes [~55-Ma Seggeurius (42)] were small (~3 to 5 kg)but gave rise to much larger species (for example, 3600-kg Barytheriumand 800- to 1400-kg Titanohyrax ulitimus), coincident with our esti-mates of ucp1 inactivation. Although large-bodied (~625- to 800-kg)hyracoids such as “Titanohyrax” mongereaui are also known from ear-lier deposits, the presence of only a single, “primitive” Seggeurius-sizedspecies (Dimaitherium patnaiki) from the early Priabonian (~37 Ma)suggests that gigantism evolved independently in Middle and Late Eo-cene hyracoids (43). " |
10.1126/sciadv.1602878 |