Both members of a couple are heterozygous for a recessive mutation that causes tay-sachs disease (normal = a, mutant = a. if they have six children, what is the probability of them having two affected children and four unaffected ones?

4. multiple crosses were made between true-breeding lines of black and yellow labrador retrievers. all the f1 progeny were black. when these progeny were intercrossed, they produced an f2 consisting of 91 black, 39 yellow and 30 chocolate. a. propose an explanation for the inheritance of coat color in labradors. b. propose a biochemical pathway for coat color determination and indicate how the relevant genes control coat coloration.