what I wrote in pencil might be wrong III The pedigree below

III. The pedigree below is of the rare disorder, Bloom syndrome, which causes dwarfism and increased cancer rate in affected individuals. A A A aa A- da

Solution

Bloom syndrome :

it is inherited as an autosomal recessive genetic trait

what is the probabaility that individual IV-1 AND IV-3 WILL HAVE A CHILD BLLOM S SYNDROME

IV-1 ----------normal --------GENEOTYPE ------------- Aa    or     AA

AND

IV-3-------------normal ------------GENEOTYPE-------- Aa    or     AA

As it is a recessive disorder , requires double dose of recessive allele for expression

A----------NORMAL ALLELE,

abnormal allele-------a

Aa      x Aa

A

a

A

Normal                  AA

Normal carrier Aa

a

Normal carrier       Aa

Affected    aa

Answer = (1/4) = 0.25

	A	a
A	Normal                  AA	Normal carrier Aa
a	Normal carrier       Aa	Affected    aa