The Dynand Line is part of the Dryad cluster of three lines, which Professor Maras was the first to suggest was a low probability cluster that diverged from higher probability lines around 70,000 years ago.
Recent research undertaken on the Sultan line on DNA comparison supports his theory and suggests that the divergence occurred during a genetic bottleneck in human evolution when the population plunged to somewhere between 5,000 and 10,000 individuals. While the initial cause of this population crash had been initially suggested as being caused by the catastrophic eruption of the Toba volcano in Indonesia, and the subsequent cooling of the world’s climate, more recent research has suggested that the bottleneck may have been the result of an increase in spontaneous abortions as the result of a viral agents, or series of viral agents.
For most lines the human species eventually developed some native resistance to the virus, however on the Dryad cluster, this never occurred, and an alternate strategy occurred with a preponderance of female numbers of 6 females to every male birth.
For higher probability lines, Fisher’s principle explains that under most circumstance the sex ratio for any species will return to 1:1. That is, if male births are less common than females, a newborn male will have better mating prospects than a newborn female, and can therefore expect to have more offspring. Over time the genes for male-producing tendencies spread, and male births become more common. As the 1:1 sex ratio is approached, the advantage associated with producing males gradually disappears. It appears that this is what happened on most lines who had the preponderance of females births, however, in the Dryad cluster the Historical Inevitability school of thought would hold that the lines split off because a culture had arisen that focused on the worth of the female, and which was sufficient to counteract Fisher’s Principle.