You’re Descended from Royalty and So Is Everybody Else

Re:You’re Descended from Royalty and So Is Everybody Else by jonsen on Thursday January 04, 2018 @12:24PM (#16072087)

Humans have 23 chromosome pairs. That is 46 halves. Therefore you can maximally have a common chromosome half with 46 people at any ancestry level.

[ Parent | on HN ]

Re:You’re Descended from Royalty and So Is Everybody Else by unit91 on Thursday January 04, 2018 @02:55PM (#16073476)

I see the downvotes, but genetics isn't my thing. Can somebody in the know explain what the error is? Thanks.

[ Parent | on HN ]

Re:You’re Descended from Royalty and So Is Everybody Else by patall on Thursday January 04, 2018 @03:19PM (#16073698)

I cannot say why he is downvoted but there are some mistakes in his comment. First, there would be 47 shareable elements as you have 46 chromosomes plus the mitochondrial genome. And then, any of the 46 chromosomes (besides the Y chromosome in males) can and do exchange segments with its homolog/sister chromosome of the same type (crossing over or recombination). While this does not happen all the time, it does happen, so you from some points in history you are inherating your genome from many more ancestors.

[ Parent | on HN ]

Re:You’re Descended from Royalty and So Is Everybody Else by improbable22 on Thursday January 04, 2018 @03:07PM (#16073597)

Chromosomes don't stay intact like (it sounds like) jonsen is assuming. Instead they cross-over or re-combine to make never-before-seen strands -- the new strand has one end from one copy & the other end from the other copy.

There are maybe 2-3 cross-over events per chromosome per generation in humans, e.g. https://biology.stackexchange.com/questions/19005/how-many-r... .

[ Parent | on HN ]