Hello Again!
On the last message to keep it short, I failed to stress that the chromosomes that we get
from each parent is random. We get half or 50% from each parent. The exception is the sex
chromosome (X or Y) that we inherit from our biological father.
Gene Zubrinsky writes:
At every generation between an early one and ourselves, random factors operate that are
likely to cause an indeterminate number of genes to drop out. The more distant the
generation, the more likely it becomes that we carry no genes whatsoever of certain
ancestors. This is why it’s appropriate to distinguish between genealogical ancestry and
genetic ancestry.
He is correct. Every generation and the children of each biological pairing inherit a
random selection chromosomes . Each generation and those children get a random mix of what
is left. After several generations, some genetic ancestor donors can literally be excluded
by randomness causing gaps in your genetic ancestry. And the subsequent loss of genetic
atDNA when compared with your genetic atDNA lineage. In essence, atDNA genetic lost
cousins.
My use of the 50%, 25%, 12.5%, et cetera for each generation back into time is for general
averages or similar to a Bell Curve diagram. Randomness and probability come into play
during this repeated cycle of births and generations. This is why I provided the link to
the image regarding Theoretical probabilities.
As Gene mentions, it is important and appropriate to distinguish between genealogical and
genetic ancestry. For those familiar with genetic genealogy triangulation, it is needful
to clearly state or show how the genetic and genealogy is related. See more at:
https://isogg.org/wiki/Triangulation
Please remember the genealogy is the facts and figures. Genetic testing is a tool to help
us with our genealogy. The combination of the two is genetic genealogy. This is
different from human anthropology that uses non-genealogical data points to construct a
general human tree such as X or Y haplogroups and smaller hapoltypes.
Again, Merry Christmas & Happy New Year!
John R. Carpenter
La Mesa, CA USA
Carpenter Cousins Project - Our main support page!
https://carpentercousins.com