Answer:
25%
Explanation:
<u>Generally in a pedigree charts</u>, <u>Circles are used to represent females in the charts, while squares for males</u><u>.</u>
To show the presence of an investigated diseases, <u>the circle or square is painted black</u><u>, </u>
<u>to show that the individual is a carrier the shape is painted half way.</u>
while to indicate an individual <u>who is normal for the inherited disorder, the shape is not shaded at all.</u>
<u />
<u>Therefore, in this scenario,</u>
the un-shaded square is a normal male,not caring allele for SS.
the half-shaded circle and square are carrier of SS allele.
the completely shaded square male carries a sickle cell traits,he is homozygote recessive for the allele, He must have inherited the traits from each of the heterozygote dominant genes of the parents AS blood groups.
Based on the Mendelian inheritance; this is 25%, since 4-offspring were involved, assuming each is 25%, then 1/4= 25/100.