Widow's Peak, a Pointed Hairline on the Forehead, Is a Genetic

question 46

Multiple Choice

Widow's peak, a pointed hairline on the forehead, is a genetic trait caused by a dominant allele. It can be traced back through a family's history using pedigree analysis.
The pedigree shown here is of three generations of a family. Notice that some individuals (shown in gray) have a widow's peak (W = dominant allele and w = recessive allele) .
-This pedigree supports the fact that widow's peak is due to a dominant allele, because if it were due to a recessive allele and both parents show the recessive phenotype, then ________.

• A)half of the sons would have a widow's peak
• B)all of the offspring would have a widow's peak
• C)none of the daughters would have a widow's peak
• D)all of the daughters and none of the sons would have a widow's peak

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Definitions:

Fibrocartilage

A type of tough, very dense, and fibrous cartilage found in places requiring great tensile strength such as intervertebral discs and the menisci.

Elastic Cartilage

A type of flexible cartilage that contains elastic fibers, enabling structures like the ear and epiglottis to bend and return to their original shape.

Compact Bone

the dense, hard layer of bone tissue that lies underneath the periosteum, providing strength and structure to bones.

Dense Fibrous

Refers to connective tissues rich in collagen fibers that provide strength, support, and flexibility to structures such as tendons and ligaments.