Briefly describe the two competing theories regarding the or

Briefly describe the two competing theories regarding the origin of Homo sapiens and its distributional expansion from its origin in Africa. What does the genetic data say about these two hypothesis, which genes are most useful for these analyses and why? Given a large section of a genome, say a complete chromosome, how could you locate genes?

Solution

1.Out of Africa-This population was first of H.Erectus to travel out of Africa and is what caused there to be a difference in the populations of humans that would come about in Africa.Homo sapiens evolved in Africa and then made their way out into the old world replacing all other human populations without interbreeding,and slowly but surely colonized the world.The Out-of-Africa theory states that an initial wave of Homo erectusleaves Africa 2 million years ago. After they leave,they begin to branch off into several different species such as H.heidelbergensis andH. neanderthalensis.Then modern H.sapiens evolve in Africa about 100,000 years ago and spread across the globe in a second wave of migration and replaced all the old species that were formed.

Multiregional- The evolution of Homo Sapiens.Homo Erectus migrated out of Africa and dispersed themselves throughout the old world.Populations are isolated which then evolved and became a species that we are today,there was some interbreeding,so we can see some change from then to the modern human also because of frequent gene flow.There was a lot of prevention from branching out and isolation so this helped evolve into the Homo Sapiens.They spread throughout Europe and Asia.The Multiregional theory states that the Homo erectus species left Africa 2 million years ago and settled around different regions of the world.

2.In support of an African origin,H.sapiens show the highest level if genetic variation in mtDNA in African populations.This implies that H.sapiens first arose in Africa and had time to accumulate genetic diversity.Using genetic distance as a measure of time,it is suggested that H.sapiens arose between 100,000 and 400,000 years ago in Africa.Against the multiregional theory there is data that states the low amount of genetic variations of modern human populations suggest our origins may reflect a small founding population.Analysis of mtDNA supports the view that a small population of H.sapiens,numbering from about 10,000 to 50,000 people,left Africa somewhere between 50,000 and 100,000 years ago.

3.By using the sequence inspection we can locate genes because genes are not random series of nucleotides but have distinctive features.Doing this determines whether or not a sequence is a gene.