Several Members of the Fitzsimmons Family Have Polydactyly,and They Differ

question 27

Multiple Choice

Several members of the Fitzsimmons family have polydactyly,and they differ in their numbers of extra fingers and toes.Yet,certain relatives who should have extra digits don't,such as Megan Fitzsimmons.She has two children,a son with two extra fingers and a daughter with an extra toe,and her father has an extra digit on each hand and foot.Polydactyly in this family is

• A)variably expressive and incompletely penetrant.
• B)invariably expressive and completely penetrant.
• C)pleiotropic and a phenocopy.
• D)dominant and recessive.

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Definitions:

My/o

Prefix related to muscle or muscles.

Fasci/o

A prefix in medical terminology referring to fascia, the connective tissue surrounding muscles, organs, and other structures.

Clavicle

A lengthy bone acting as a support between the scapula and the sternum, also referred to as the collarbone.

Dactyl/o

A prefix relating to the digits of the hands or feet (fingers or toes).