We have identified a Y-chromosomal lineage with several unusual features.
Could biological selection be responsible Although this possibility cannot be entirely ruled out, the small number of genes on the Y chromosome and their specialized functions provide few opportunities for selection…It is therefore necessary to look for alternative explanations.
From the perspective of moderns, who tend to conceive of historical patterns and forces in economic, or at least ideological, terms, this fixation on blood descent seems ridiculous.
I suspect that many pre-modern people, who were accustomed to small family groups and kin networks in a way we are not, would find our own surprise rather perplexing. First, they discovered that there was a particular Y chromosomal haplotype, a set of unique genetic markers, which was found across much of Asia.
Observe the greater complexity of the network for other Y lineages.
Here is the text which explains the factors behind the rise of the Genghis Khan haplotype: This rise in frequency, if spread evenly over ~34 generations, would require an average increase by a factor of ~1.36 per generation and is thus comparable to the most extreme selective events observed in natural populations, such as the spread of melanic moths in 19th-century England in response to industrial pollution…We evaluated whether it could have occurred by chance.