Odds of no recombination in a generation:
Odds of at least one recombination across segment in a generation:
Odds of inheriting entire segment:
Odds of not inheriting segment at all
Note: It should not be shocking that a small segment may have a high likelihood of being recent, as we are exploring a single segment, not total cM. Put another way, if a small matching segment between two donors on a chromosome is very recent in age, they will also probably share many other matching segments in addition to the segment being explored in this simulation.
Note that this tool assumes that a generation spans 25 years, but the number in the years column will be dilated by a factor of 1.5 if the segment is on the X chromosome to account for the lack of recombination in father-daughter X transmission.
Note: Employing a dilation factor in this manner does not take into account special boundary conditions for close-relative X relationships. However, this method accurately models the effect of the lopsided nature of X inheritance over longer time spans. A future improvement to the tool, perhaps in version 2, would be to account for the close relative boundary conditions for more accurate results when a user runs this calculator on a large segment on the X chromosome. Since this demonstration is intended to provide an understanding of the inherent "stickiness" of small segments, a dilation model should be sufficiently accurate for our purposes (illustrating the age ranges of a small segment on the X chromosome).