Agreed, Marty. David has also been doing some research into whether or not segregation of segments during meiosis is random and, if not, what the implications might be for genetic genealogy. An example of relevance is stem cells. During mitosis (cell reproduction that does not involve meiosis, so doesn't produce gametes), stem cells need to prevent double-strand breaks, segment segregation, crossovers, and allele mutations. The "parent" stem cells have some mechanism, genetic or epigenetic, that seems to protect them from these activities which could cause deterioration of the basal, parent cell line over time. We don't really know if there are similar, or a subset of, these types of segmentation inhibitions in play during meiosis.
We do know that recombination in meiosis isn't entirely random--there are areas of the chromosome where crossover is suppressed; there are tens of thousands of identified recombination hotspots; and the function of genetic linkage and linkage disequilibrium act to keep blocks of contiguous alleles together during crossover--but if there is an additional mechanism in play inhibiting segment segregation it might lead to a better understanding of genetic distance probabilities in at least some areas of the chromosomes.
Sorry; shop-talk. But I hope David finds something interesting in that research and if so continues on to publish it.
