The matrilineal genographic family tree is mapped out through markers in the mitochondrial DNA (mtDNA). Unlike most DNA, mtDNA is inherited from one parent only – the mother. This means that everyone’s mtDNA has exactly the same sequence of 16,569 nucleotides as their mother and, consequently, to their mother’s mother and so on. However, on the very rare occasions where a mutation occurs, a child’s mtDNA will be different to their mother’s at one nucleotide, e.g. a G in the sequence might become an A. If that child is a female, she will then pass this mutation on to her children and they, if they are female, will pass it on to their children, and so on. Any of her descendants along a continuously female line of descent will carry the same mutation. Hence, it can be determined from the presence of that particular mutation in anyone’s mtDNA sequence that they share that same female individual in whom the mutation first occurred as a common ancestor along their maternal line of descent.
Each time a mutation occurs, a new branch or subbranch (haplogroup or subclade) is formed in the matrilinear genographic family tree, with all bearers of the mutation belonging to the same branch. By tracking the geographic locations of these haplogroups, particularly among indigenous populations, the shared ancestry of different population groups can be determined and the long-term patterns of human migration estimated.
Kai's matrilinear genographic family tree, as determined by his mtDNA markers, is that of haplogroup M*.
Haplogroup L3 is an early offshoot from Eve's mitochondrial genetic sequence. L3 appears only in Africa.
Around 80,000 years ago two mutations gave rise to two offshoots from L3 - the M and N haplogroups from which all subsequent Eurasian lineages are descended.
About 50,000 years ago a period of warmer temperatures and moist climate made significant parts of the Sahara region habitable. This climatic shift likely spurred hunter-gatherer migrations into the Sahara and thence out of Africa into the Middle East. When the climate became dry again, the "Saharan Gateway" closed and isolated them from Africa. Instead they spread around the rest of the world.
Haplogroup M* ancestors were part of a great South Asian coastal migration that took place around 50,000 years ago. Hunter-gatherers skilled at seaside living spread along the coasts of the southern Arabian Peninsula, India, Sri Lanka and Southeast Asia. This southern coastline was drowned by rising sea levels at the end of the last ice age, likely eliminating most archaeological evidence of the migration. M* is the dominant haplogroup in India, especially southern India. It is common in Southeast Asia and also accounts for significant proportions of the populations further north in China, Mongolia and Japan.
Archaeological evidence shows that fast moving migrants of the southern coastal M* migration reached Australia 40,000 to 60,000 years ago. During the glacial Pleistocene era (around 50,000 years ago) sea levels were up to 100 meters lower than today. Much of present day Indonesia was joined in a single landmass known as Sunda and was separated by only 100 kilometers from the landmass known as Sahul, comprised of present day Australia and New Guinea. This facilitated the migration through the islands of Indonesia and to Australia.
Although people of the M* lineage migrated through Indonesia to Australia, Indonesia's current population (including Kai's ancestors) is believed to have descended from more recent migrations, largely by those also of the M* lineage whose earlier migrations had only taken them as far as India or Southeast Asia. The major wave of migration, from which most of Indonesia's population seem to have descended, began about 5500 years ago from China and Southeast Asia bringing with it the Austronesian language family of which the major present-day Indonesia languages are part. Austronesian languages are also found in Taiwan, the Philippines, Vietnam, Cambodia and Malaysia, indicating that it may have spread from these locations before also spreading into the South Pacific islands.
However, Indonesia is believed to have been inhabited earlier than this by migrations from India or Burma. Subsequent to the the Austronesian migrations, from the first century AD, Indonesia came under influence, likely including migration, from India. This influenced the rise of Buddhist and Hindu kingdoms such as the Sailendra kingdom in Java. Later still it was heavily influenced by Arab traders bringing Islamic religion and cultural influences.
Recent Y-chromosome research on Balinese men suggests a genetic contribution to the population of about 2.2% from pre-neolithic, pre-Austronesian lineages, 83.7% from the Austronesian migrations and 12% from the more recent migrations from India.*