Did the Sinhalese come from South India ?

My father is a Sinhalese man from the south of Sri Lanka. He has the genetic marker Haplogroup L. Marker M20 which is found in more than 50 percent of the men living in South India. Haplogroup L. Marker M20 is rarely found outside of India. In Middle Eastern populations the frequency of this genetic marker is one to two percent. So can it be that the people who became the Sinhalese came from South India ?

The following section is a summary of the genetic testing results my father received courtesy of the National Geographic Human Genographic Project. If you want to participate in this project, go to National Geographic: The Genographic Project

Please note that the process is completely anonymous.

Each of us carries DNA that is a combination of genes passed from both our mother and father, giving us traits that range from eye color and height to athleticism and disease susceptibility. One exception is the Y-chromosome, which is passed directly from father to son, unchanged, from generation to generation. Unchanged, that is unless a mutation—a random, naturally occurring, usually harmless change—occurs. The mutation, known as a marker, acts as a beacon; it can be mapped through generations because it will be passed down from the man in whom it occurred to his sons, their sons, and every male in his family for thousands of years. Each marker is essentially the beginning of a new lineage on the family tree of the human race. Tracking the lineages provides a picture of how small tribes of modern humans in Africa tens of thousands of years ago diversified and spread to populate the world.

Fast facts about M20 Marker "The Indian Clan"
Time of Emergence: 30,000 years ago
Place of Origin: India or Middle East
Climate: Ice Age
Estimated Number of Homo sapiens: Hundreds of thousands
Tools and Skills: Upper Paleolithic

My father's ancestors were part of the M9 Eurasian Clan that migrated south once they reached the rugged and mountainous Pamir Knot region. The man who gave rise to marker M20 was born in India or the Middle East. My father's ancestors arrived in India around 30,000 years ago and represent the earliest significant settlement of India. For this reason, haplogroup L is known as the Indian Clan.

Although more than 50 percent of southern Indians carry marker M20 and are members of haplogroup L, my father's ancestors were not the first people to reach India; descendants of an early wave of migration out of Africa that took place some 50,000 to 60,000 years ago had already settled in small groups along the southern coastline of the sub-continent.

Mitochondrial DNA (mtDNA), which is passed from a mother to her sons and daughters can be tracked in a somewhat similar fashion as Y chromosome data. It provides some tantalizing clues as to what may have happened when members of the Indian Clan and the Coastal Clan met. The mtDNA of people in this region preserves evidence of the early coastal dwellers in the female lineage, but Y-chromosome frequency for the Coastal Clan is very weak—around 5 percent in southern India, and even less frequent going farther north. These data suggest that the descendants of the Indian Clan may have mated with the women of the earlier coastal population, but that the coastal men were killed, driven off, or otherwise prevented from reproducing.