To work out the probability of a child inheriting a genotype, you see how many times it comes up and divide it by 4 then times by 100 for a percent.

To work out phenotype probability you work out how many times they will express a characteristic and divide it by four then times by 100 for a percent.

If we say in this diagram the B represents brown hair and b represents red hair

(The capital letter is always dominant)

scienceaid |

The likely hood of the chlid carrying one allele for brown and one for red (Bb) is two out of four:

2/4= 0.5

x100= 50%

The likely hood of the child having red hair (red hair is recessive so they both have to be red (bb)) is two out of four: also 50%

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