Part of Lesson Plan: Punnett Square Discovery

Activity Overview / Details

Now that you all understand how to do a simple Punnett square ... get ready, we are going to add a trait to your cattle and see what kind of calves you end up having to market. Ready? You will need to capture the details of how to set up a bigger Punnett square that just four squares...it is now going to be 16!



1. You remember the black cattle and red cattle scenario, well, now we are going to add polled vs horned trait to your cattle.



2. Polled is dominant to horned (the easist way to dehorn cattle is to use a polled bull, no blood involved!)



3. B = black, b = red, H = polled, h = horned



4. What two traits are dominant? What two traits are recessive?



5. Lets set it up: you have a homozygous black polled bull bred to a red, horned cows. What do the offspring look like?



Bull = BBHH x Cows = bbhh



to illustrate the cross show the class how to align the alleles

BH BH BH BH x bh bh bh bh

Results are: all the calves will be BbHh or heterzygous black and polled