Topic 11 - Pedigrees

Question 1

Pedigree

Answer 1

A family tree of parents and offspring, showing inheritance of particular traits of interest.

Question 2

Clear squares

Answer 2

Sign used to represent unaffected males in a pedigree.

Question 3

Clear circles

Answer 3

Sign used to represent unaffected females in a pedigree.

Question 3

Clear diamonds

Answer 3

Sign used to represent an unaffected individual with unknown sex in a pedigree.

Question 3

Shaded shapes

Answer 3

Used to represent affected individuals in a pedigree.

Question 4

Offspring Line

Answer 4

Vertical line from the center of the mating line to the center of the offspring symbol or to the sibling line.

Question 5

Marriage/Mating

Answer 5

Horizontal line connecting 2 symbols at the center of each symbol.

Question 5

Sibling Line

Answer 5

Horizontal line above the offspring and connecting to them through vertical lines.

Question 6

Double lines between symbols

Answer 6

Indicate consanguineous marriage.

Question 7

Autosomal dominant

Answer 7

Males and females are equally likely to be affected; affected offspring have at least one affected parent; unaffected offspring are homozygous recessive; trait does not skip generations.

Question 8

Autosomal recessive

Answer 8

Males and females are equally likely to be affected; affected offspring often have unaffected parents; trait often skips generations.

Question 9

x-linked dominant

Answer 9

Males and females are equally likely to be affected; all daughters of an affected father are affected, but no sons; affected sons always have affected mothers; trait does not skip generations.

Question 10

x-linked recessive

Answer 10

Males are affected more frequently than females; trait is never passed from father to son; trait often skips generations.