MathBench > Probability

Linked Genes and Recombination
Advanced Punnett

A hybrid family

 

Mrs. Smiley ET/et
Mr. Smiley ET/et

Try the Punnett square for this hybrid family. Both Mom and Dad look normal, but what will their kids look like?

If you're confused about what combinations are possible, remember that we're assuming (for the moment) that the chromosomes can't break apart. So what's on the left of the slash MUST stay together, and likewise what's on the right MUST stay together.

As we've been saying, each parent has two possible gamete types. They combine to make three genotypes, and 2 phenotypes.

The phenotypes are all normal vs. rabbit-toothed and bug-eyed, in a 3:1 ratio. (in other words, most of the kids are normal and a few are double-weirds).

If you think this sounds a lot like a single-locus cross, you're right... but don't start to think it's always that easy -- go to the next page instead...