Ground tit

Abstract: Pseudopodoces humilis (Hume’s Ground-Jay) is a small passerine bird that inhabits the high rocky steppes of the Tibetan (Qinghai‐Xizang) Plateau Although it was long classified as a small species of ground jay ( Podoces ), two previous anatomical studies cast doubt on its assignment to the Corvidae (crows and jays) We studied the evolutionary relationships of Pseudopodoces using three independent datasets drawn from comparative osteology, the nuclear c- myc gene, and the mitochondrial cytochrome b gene All three datasets agree on the placement of Pseudopodoces in the family Paridae (tits and chickadees) The cytochrome b data further suggest that Pseudopodoces may be closest to the Great Tit Parus major species group Pseudopodoces is the only species of parid whose distribution is limited to treeless terrain Its evolutionary relationships were long obscured by adaptations to open habitat, including pale, cryptic plumage; a long, decurved bill for probing in crevices among rocks or in the ground; and long legs for terrestrial locomotion Despite these accommodations to a novel adaptive zone, its evolutionary affinity with the Paridae is clearly expressed in comparative osteology and genetics, and is supported by its habit of nesting in cavities

Abstract: Species that undertake altitudinal migrations are exposed to a considerable seasonal variation in oxygen levels and temperature. How they cope with this was studied in a population of great tit (Parus major) that breeds at high elevations and winters at lower elevations in the eastern Himalayas. Comparison of population genomics of high altitudinal great tits and those living in lowlands revealed an accelerated genetic selection for carbohydrate energy metabolism (amino sugar, nucleotide sugar metabolism and insulin signaling pathways) and hypoxia response (PI3K-akt, mTOR and MAPK signaling pathways) in the high altitudinal population. The PI3K-akt, mTOR and MAPK pathways modulate the hypoxia-inducible factors, HIF-1α and VEGF protein expression thus indirectly regulate hypoxia induced angiogenesis, erythropoiesis and vasodilatation. The strategies observed in high altitudinal great tits differ from those described in a closely related species on the Tibetan Plateau, the sedentary ground tit (Parus humilis). This species has enhanced selection in lipid-specific metabolic pathways and hypoxia-inducible factor pathway (HIF-1). Comparative population genomics also revealed selection for larger body size in high altitudinal great tits.