Grazings Place in Plant Evolution

Evolution can be defined as the change in the genetic composition of a population over time. According to a new study grazing pressure and pollination can also affect the genetic composition of plant populations. Researchers at Uppsala University and Stockholm University investigated these variables affect on two distinct morphs of Birds Eye Primrose population: a shorter plant with flowers produced close to the ground and a taller plant with flowers produced higher above the ground. The taller morph attracts pollinators with more ease than the shorter morph but at the cost of predation by grazers and seed predators. A field experiment showed that the pressures from either grazing or pollination determined which reproduced more successfully. Over an eight year span, results showed that changes in grazing pressures shifted the genetic frequency of the population with short plants having greater reproductive success than taller plants demonstrating that grazing pressure affects not only which plants occur more frequently but also the genetic composition of those populations.


http://www.sciencedaily.com/releases/2013/10/131021153210.htm
http://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs143_013583.pdf

Genetic Diversity in Indian Populations and Its Health Implications

 

Lalji Singh, PhD, Director of the Centre for Cellular and Molecular Biology at the Council of Scientific and Industrial Research (CSIR) in India,  has been undertaking a study on the evolution of human populations, focusing specifically on genetic diseases.  While a popular focus for many researchers,  specific data on the origin and frequencies of genetic diseases in India has been relatively sparse.  India has "one of the most genetically diverse populations in the world."  This diversity is represented by the anthropologically well-identified 4,635  populations that share little to no gene flow between them.  This is a result of the culutrual, social, and geographical boundaries that have bolstered the propensity of interbreeding within individual populations.  Taking 132 samples from 25 of these major populations, each group representing a major piece of Indian life, location, and culture,  Singh analyzed and determined that there were originally two gentically independent divergent populations.  Having the most similar genetic composition to the Middle Easterners, Central Asians, and Europeans are the Ancestral Northern Indians while the other major group, the Ancestral Southern Indians, have a genetic affinity that aligns solely with the populations currently within the region.