Re: HYB: pink probabilities
- Subject: [iris] Re: HYB: pink probabilities
- From: "Neil A Mogensen" n*@charter.net
- Date: Fri, 8 Jul 2005 15:11:16 -0400
- List-archive: <http://www.hort.net/lists/iris/> (Web Archive)
A Punnett square of a tttt X TTtt would look like this:
TT Tt Tt tT tT tt
_________________________
tt | TTtt Tttt Tttt Tttt Tttt tttt
tt | TTtt Tttt Tttt Tttt Tttt tttt
tt | TTtt Tttt Tttt Tttt Tttt tttt
tt | TTtt Tttt Tttt Tttt Tttt tttt
tt | TTtt Tttt Tttt Tttt Tttt tttt
tt | TTtt Tttt Tttt Tttt Tttt tttt
which gives 6/36ths, or one out of six "tttt" recessives, as we've
indicated.
Think of it this way: The gametes are chromosomes 1+2, 1+3, 1+4, 2+3, 2+4,
3+4 =six possible gametes (assuming random pairing).
Tttt X Tttt gives
Tt Tt Tt tt tt tt gametes for both parents. The square produces
36 possible results. Of these, 9 are tttt. That gives a ratio of 1 out of
4 tttt possible.
TTtt X Tttt gives 3 out of 36, or 1/12th tttt results.
TTtt X TTtt gives 1 out of 36 tttt results, again assuming random pairing of
the four chromosomes. That isn't always the case, however.
Does this help, Linda?
Neil Mogensen z 7 Reg 4 western NC mountains
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