Biology Forums - Study Force

In certain families in Norway, woolly hair is passed down through the generations.  In order for children to have this trait, at least one parent must have woolly hair.  How is this trait most likely inherited? Draw a pedigree for a family where one of the three children and both parents have woolly hair.  Identify the genotypes and phenotypes for each individual in the family.  Whose genotype can you not be certain of?

This should answer your question!

Since the children require at least one of the parents with woolly hair to have woolly hair, it means that the trait is inherited in an autosomal dominant manner. The children will therefore express the trait if they get at least one allele for the trait. Let the dominant allele be represented as W and the recessive allele be represented as w.

The pedigree is represented as:

[See attachment 1]

if the parents I-1 and I-2 are homozygous for the trait (WW), then all the offsprings would have woolly hair. Since there are some offsprings with normal hair, it means that the parents are heterozygous for the trait (Ww)

now Ww x Ww

gametes ----> W w W w

offsprings ---->

[See attachment 2]

In the 2nd generation (among the offsprings), the genotype of the child with woolly hair could be either WW or Ww. therefore it is not certain whether the offspring (II-2) is WW or Ww

Thanks!

Thank you

Thanks!