Genetics Rabbit Example

Used this whole example from www.biotopics.co.uk/newgcse/rabbitgenetics.ppt and used a little of my previous knowledge from last year in 8th grade when we learned a little about genetics.

This is a "family tree" of rabbits. Right now Im focusing on coat color as an example. The offspring proportion I'm using is the estimated, but not always that exact.

MOM                                                    DAD

Albino (Recessive)              Brown (Dominant)
aa                                                          BB

OFFSPRING: 100% Dominant (BROWN)

BaBa
BaBa


Now take one of those and breed it with another one...

Brown (Dominant)                    Brown (Dominant)

Ba                                               Ba

Dominant(Brown)=75%    Recessive(Albino)=25%

                BB 
                  Ba

Ba

  aa 

So the offspring of two BROWN rabbits don't always have to be brown as well, because if they BOTH have an heterozygous genotype, then their recessive genes could make a recessive baby.

If you have a dominant phenotype, then you COULD have an invisible recessive allele in your genotype.

This is why sometimes your mom and your dad could both have brown hair, and all of your brothers and sisters have brown hair too, but you end up with blonde hair.