Re: HYB: punnett squares for TBs (Facebook discussion)
iris@hort.net
  • Subject: Re: HYB: punnett squares for TBs (Facebook discussion)
  • From: C* C* <i*@aim.com>
  • Date: Sat, 8 Feb 2014 11:55:31 -0500 (EST)
Kidd's analysis of Keith's data showed plicata is far enough away from kinetechore to be independent. Thus tetraploid genetics operate on random sorting, rather then strictly a Punnett square assortment. But Punnett square still gives best predictions. The plants don't care what the genes are, they will all still sort out via tetraploid genetics. It would take specific data to assess what distance genes are from kinetechore and thus how much independence. That is if you can identify a single gene affecting phenotype. As far as I know, Kidd only looked at plicata genes. Mostly as Keith was keeping good records that Kidd could use. Geneticists need lots of good data to work with. Without it you are just working at theories. That is why I'm always asking people for data, particularly on long crosses. I don't get good success rates on a lot of crosses in my problematic climate so have less data then I would like to work out gene effects. 

Chuck Chapman



-----Original Message-----
From: Linda Mann <lmann@lock-net.com>
To: iris <iris@hort.net>
Sent: Sat, Feb 8, 2014 11:42 am
Subject: Re: [iris] HYB: punnett squares for TBs (Facebook discussion)

Chuck, do you know if that has been observed for other iris genes -
patterns, rebloom, pigments?

Is 1/576 as high as the probability for this type of event gets?

On 2/8/2014 8:32 AM, Chuck Chapman wrote:
One of the special features of tetraploid genetics is the possibility 
of

doubling up on a gene that is present only once. something that is not
shown or predicted in a punnett square.

This happens as  chromosomes are doubled during meiosis, so you are
choosing from 8 choices, not four.  So  you can, for example, get a
plicata from a cross  where there is only one plicata gene in each
parent.  Kidd calculated this to be 1/576, if  plicata genes is at a
distance from kinitochore of the gene [chromosome?] it is on. Lower 
if it is close to
kinitichore. Kidd used some data from Keith Keppel to show that it 
does

happen and is not just a theory.

Chuck Chapman


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