Expert: Walter Hintz - 2/4/2010

Question
Don't know if you can give me any insight but, I have a question about dominant and recessive traits. Everyone says that if a dad is black and a mother is white, the kids will look like black because those are the dominant traits. I want to disagree with that but I don’t know for sure. The way I see it is, a dominant trait just means that those traits have a higher chance of showing through than the white, recessive traits. It doesn’t necessarily mean that 100% of the time, the kids will look more black than white. I wanted some insight on the subject, your professional opinion. If the children have one black parent and one white parent, is it ALWAYS true that they will look more black than white? Is it possible for them to look more white than black? Thanks, and hope you can help!

Answer
Hi Ashley
It is true that darker pigments dominate over lighter pigments but skin ,hair and eye color are not controlled by single genes but by multiple genes. This means that no child can look darker then the darkest parent.
Look at what happens if we consider single genes
 Let B = Black
     b = white
 Remember that genes are paired so  in this cross  BB   X  bb
  All  Children would be Bb sort of half black and half white
 Now lets cross two of the Bb     Bb  x  Bb
       B        b  

 B    BB       Bb


 b    Bb      bb

    Now the bb would most likely have white skin but we do not decide the race on the basis of just skin color because there is hair color and characteristics facial freachers etc.
 The BB may have red hair and blue eyes and the bb with white skin could have kinky hair.
 Consider President Obama. He is of mixed race and his children are darker then he is.  East Indians are darker than Obama and they are considered Caucasian.
 So we are faced with the question of what we mean when we say someone looks black or white or red or yellow.
 When we look at these facts it seems to me that these labels;black,red,yellow and white are just a lot of nonsense. I have an adopted son who is Asian and he is not yellow and my Grandfather was part Cherokee and he was not red.