Expert: Walter Hintz - 3/14/2010

Question
I saw your clue to this answer, but my teacher had added something to the problem (at the end of the problem)

This is a problem that I was given in my biology class  to set up a trihybrid punnett square, and I don't know how to set the cross up, I've typed the question as it appears on the worksheet.

-->You are a world-famous breeder of Purple-People Eaters ("PPE").  Tragically, your entire stock perishes in a fire except for two individuals.  They are both heterozygous for all three traits desired.  The three traits are as follows:

EE/Ee-two eyes        ee-one eye
HH/Hh-two horns       hh-one horn
FF/Ff-non flying      ff-flying

The traits that bring the big bucks ($100 each) are "one eyed, one horned, flying" purple people eaters.  If you breed the remaining two PPE, what distributions of traits will you get?

Of these, how many will have all three of the traits that you will be able to sell for those big bucks?

It costs $25 to raise a PPE.  Will it be cost effective (get a lot of them critters) or shall you buy yourself fresh breeding stock of a different genotype?  Briefly explain and give the best parental genotype (F2 generation) needed to make money with these critters.

Thank you

Answer
Hi helen:
The genotypes of the two left are as follows
 EeFfHh       x    EeFfHh
  And your punnett square would look like this

           EHF       EhF      Ehf      eHF          ehF       ehf



  EHF     EEHHFF    EEHhFF


 EhF



 Ehf


 eHF


 ehF


 ehf                                                         eehhff

 Now iassume that you know how to complete the punnett square. If not I started to fill it in for you. You can finish it. Upon doing so you will find the Mendelian phenotype ratio of 9:3:3:i
 The one being the one eyed,one horned,flying PPE with the genotype, eehhff.
No need to get new breedin stock just inbreed the eehhff types