Telomeres – small sections of protective DNA found at the end of each chromosome – have been repeatedly linked to ageing. But their complex dynamics remain poorly understood, especially in wild populations. Continue reading
Study identifies seven new loci associated with high-altitude living
Tibetan populations have evolved at least nine specific genetic variants to help them survive the extreme conditions of the Tibetan Plateau. Living permanently at over 4,000 m above sea level, these populations have been coping for millennia with 40% less oxygen and 30% stronger UV radiation, as well as exposure and limited food.
Mountains tend to have more species than valleys, and new research provides support for the theory that mountain formation itself might be responsible.
Yaowu Ying and Richard Ree from The Field Museum in Chicago compared regional rates of plant colonisation and speciation in the Qinghai-Tibetan plateau, a high-altitude biodiversity hotspot. Within the QTP, the Hengduan mountain region is the most biodiverse, harbouring an astonishing 12,000 species in just 500,000 km2. The authors used published datasets to compare the spread of over 4,500 plant species across Hengduan, the Central Asian Mountains and the Himalayas.
The first skeletons evolved multiple times independently because of unusually chalky seas, later becoming essential for survival even when chalk became scarce.
Calcium-based skeletons appeared suddenly in the fossil record around 550 million years ago, fundamentally changing the global carbon cycle and introducing a wealth of new predatory strategies to the sea.