Question

Drag the given black and white squares to the correct location on the chart. Each square can be used more than once. The pedigree chart shows the inheritance of an X-linked recessive genetic trait. Fill in the dashed boxes to correctly complete the chart. A basic square box

Answer 1

Based on the pedigree chart you provided, the following is the correct placement of the black and white squares:

Black squares:

• Female I-2
• Male II-2
• Male III-2

White squares:

• Male I-1
• Female II-1
• Female II-3
• Male III-1

Dashed boxes:

• Female I-1: Carrier
• Male II-1: Normal

X-linked recessive traits are more common in males than females because males only have one X chromosome. If a male inherits a recessive allele for an X-linked trait on his X chromosome, he will express the trait because he does not have a dominant allele to mask it. Females, on the other hand, have two X chromosomes. If a female inherits a recessive allele for an X-linked trait on one of her X chromosomes, she will only express the trait if she also inherits a recessive allele on her other X chromosome. If she inherits a dominant allele on one of her X chromosomes, she will be a carrier for the trait but will not express it herself.

In the pedigree chart you provided, female I-2 is a carrier for the X-linked recessive trait because she has an affected son (male II-2). Male II-2 expresses the trait because he inherited the recessive allele from his mother and does not have a dominant allele to mask it. Female II-1 is not a carrier for the trait because she has an unaffected son (male III-1). Male III-2 expresses the trait because he inherited the recessive allele from his mother.

Conclusion:- The pedigree chart shows that the X-linked recessive trait is being inherited in a classic X-linked recessive pattern. The trait is more common in males than females, and carrier females can pass the trait on to their sons without expressing it themselves.