What can I do with a ParaHet?

So, we have a ParaHet, which we know is het. for either Sharp-albino or Caramel hypo but we don’t know which. Clearly, the questions we are interested in answering are, “What are the breeding trials that could be performed to determine whether it is a het. Sharp albino or a het. Caramel hypo, and what offspring do we have the potential to produce from these breeding trials?”



The first option we will consider is breeding the ParaHet to another ParaHet. In selecting any two ParaHets at random, we can have either two het. Sharp albinos (probability ¼), two het. Caramel hypos (probability ¼), or one of each (probability ½). The Punnett squares for each of these three test crosses and the associated expected offspring summaries are shown below.







So, if we breed two ParaHets we would expect approximately ¼ of the litter to be either Sharp-albino, Caramel-hypo, or Paradigm. If there are Sharp-albinos in the litter then both parents are now known to be het. Sharp albinos. If there are Caramel hypos in the litter then both parents are now known to be het. Caramel hypos. Finally, if there are Paradigms in the litter, then we know that one parent is het. Sharp albino and the other parent is het. Caramel hypo – though we know we have one of each, we cannot tell which parent is which, but who cares….we made Paradigms from just a couple of ParaHets!



The even better news is that producing Paradigms is the most likely outcome as indicated by the probabilities above. To repeat, in choosing any two ParaHets at random, the odds are ¼ that both are het. Sharp albino and thus will produce Sharp albinos, and ¼ that both are het. Caramel hypo and thus will produce Caramel hypos. But the odds are ½ that we have one of each, and that they will produce Paradigms.



These examples also point out a further advantage of using the name ParaHet. In the cross above that produces Paradigms, the remaining ¾ of the litter consists of 1/3 normal, 1/3 het. Sharp albino and 1/3 het. Caramel hypo. It is equivalent to say that 2/3 of these are ParaHets. As such, we can simply call all of the normal appearing offspring in this litter 66% possible ParaHets (or just 66% ParaHets) analogous to the way we would arrive at the more familiar 66% het. Sharp albinos.



What Else Can I do with a ParaHet?

The other possible ParaHet breeding trials include crossing a ParaHet with a Sharp albino, a Caramel hypo, or a Paradigm (a ParaHet could also be crossed to a 100% het. Sharp albino or a 100% het. Caramel hypo; those outcomes are already described above in the analysis of the ParaHet to ParaHet cross). Each of these crosses and the possible outcomes are shown below. The Punnett squares on the left show the case in which the ParaHet is a het. Sharp albino, and those on the right show the case in which the ParaHet is a het. Caramel hypo. Note that in each case, the phenotypes of the offspring allow us to determine whether the parent ParaHet is a het. Sharp albino or a het. Caramel hypo.















We have now shown all of the possible crosses that can be performed to determine if a ParaHet is a het. Sharp albino or a het. Caramel hypo, and the expected offspring from all of those crosses. Obviously, crosses that also include another trait, such as a Motley het. Sharp albino to a ParaHet, can also be done, but the other trait (Motley in this case) will be controlled by a different gene and will have no effect on the genetics of the Paradigm locus - at least as far as we know today!



Such multi-trait crosses can also be evaluated using a Punnett square (4x4 for two traits, 6x6 for three traits, etc.), but it gets very tricky to correctly distribute the alleles in the parent’s boxes of the square as the square gets larger and it is easy to make mistakes. In some future posts we will present examples of some multi-trait crosses that include the Paradigm trait, along with a simpler statistical approach to evaluating these crosses – and you don’t even have to know anything about statistics to do it!



Thanks for looking,



Steve Reiners




www.BoaMorph.com

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