An international team, including researchers from The Open University, has discovered that highly diverse plant life found in China can be traced back to the formation of ancient mountain ranges.<\/p>\n
In a new study, published in Science<\/a>, researchers examined the plant life in China\u2019s Hengduan Mountains, the Himalaya Mountains, and the Qinghai-Tibet Plateau. Using DNA to build family trees of species, they learned that the diversity of plants in that region today, and the original source of many of our garden plants, can be traced back to mountain ranges 30 million years ago, and monsoons that came later. It\u2019s a concrete example of how climatic and environmental changes influence life on Earth.<\/p>\n The study focuses on plants growing above the treeline (called the alpine zone) in the Hengduan Mountains of southwestern China. Researchers wanted to find out how plants are distributed in the alpine regions of the Hengduan Mountains, Himalaya, and Qinghai-Tibet Plateau, and how they got there in the first place. To figure it out, they turned to phylogenetic reconstructions: essentially, using DNA and key pieces of fossil evidence to piece together the plants\u2019 family trees, going back tens of millions of years.<\/p>\n Robert A. Spicer<\/a>, Emeritus Professor of The Open and co-author on the paper, said:<\/p>\n \u201cThe Tibetan region hosts one of the world\u2019s great biodiversity\u00a0\u2018hotspots\u2019 but it is under threat from climate change and other forms of human disturbance. Normally we would use fossils to understand ancient vegetation history and so how to best conserve this precious ecosystem, but alpine plants growing high in the mountains simply do not get preserved, so we had to try a different\u00a0approach.<\/p>\n \u201cThis study blends using DNA to reconstruct plant ‘family trees’ with ‘hard core’ geology in order to reconstruct landscape evolution across the Tibetan region. As with most modern science, advances come with the marriage of disciplines and the offspring of this marriage is a new understanding of when and how one of the world\u2019s great biodiversity \u2018hotspots\u2019 was formed.\u201d<\/p><\/blockquote>\n The team compared the DNA of different plant species that live in the region, determining how closely related they were to each other and how they evolved. If you have DNA sequences for a variety of different plants, by looking at the differences in their DNA and using fossil plants as benchmarks for how long it takes new species to arise, you can make an estimate as to how long ago their common ancestor lived and figure out the family tree that makes the most sense.<\/p>\n In this study, the research team were able to trace the origins of alpine plants in the Hengduan, Himalaya, and Qinghai-Tibet Plateau and found that they represent the world’s oldest temperate alpine area. Many of the plants first evolved in the Hengduan Mountains. Then, as the Indian tectonic plate collided with Asia, slowly creating new mountains, a bunch of new habitats formed up the mountains\u2019 sides, and in the valleys below. As the new mountains formed, the region began to experience more intense monsoons, possibly because the mountains altered the prevailing winds, creating new weather conditions.<\/p>\nUsing plant DNA to reconstruct family trees<\/strong><\/h2>\n
Evolution of the mountain ranges<\/strong><\/h2>\n