Topic 12-1

Question 1

a pictorial representation of a family history, essentially a family tree outlining inheritance of one or more characteristics

Answer 1

pedigree

Question 2

horizontal lines in pedigrees represent:

Answer 2

matings b/w mother and father

Question 3

vertical lines in pedigrees represent:

Answer 3

they connect a mating to a child or children

Question 4

males are represented by _______ in pedigrees

Answer 4

squares

Question 5

females are represented by _______ in pedigrees

Answer 5

circles

Question 6

people with unkown or unspecified sex are represented by _______ in pedigrees

Answer 6

diamonds

Question 7

the presence of a certain trait are represented by:

Answer 7

coloured in shapes

Question 8

if a person is suspected to have the mutant gene but does not display the trait they are called:

Answer 8

obligate carriers

Question 9

obligate carriers are represented by _______ in pedigrees

Answer 9

a dot and not a filled in shape

Question 10

pedigrees are initiated when a particular family member with a trait is studied. this family member is called the:

Answer 10

proband

Question 11

probands are designated with:

Answer 11

a “P” and an arrow pointing at the person/shape

Question 12

limited numbers of offspring make ________ impossible to discern, thus we must be _______

Answer 12

mendehlian ratios, genetic detectives

Question 13

autosomal recessive traits:

Answer 13

• normally appear with equal frequency in both sexes
• occurs only when a person inherits an allele from each parent
• if trait is rare, traits can skip generations
• if progeny keep mating outside the family, then the trait can be passed down for many generations without appearing

Question 14

when considering autosomal recessive traits, traits are more likely to appear:

Answer 14

among progeny of related parents

Question 15

mating between closely related people

Answer 15

consanguinity

Question 16

how is consanguinity represented on a pedigree?

Answer 16

parallel horizontal lines

Question 17

what is an example of an autosomal dominant trait?

Answer 17

familial hypercholesterolemia

Question 18

what is familial hypercholesterolemia?

Answer 18

a disease characterized by a defect in cholesterol transport which leads to greatly elevated cholesterol

Question 19

familial hypercholesterolemia in heterozygous individuals:

Answer 19

• blood LDL levels are 2x normal levels
• susceptible to heart attacks by age 35

Question 20

familial hypercholesterolemia in homozygous individuals:

Answer 20

• blood LDL levels are 6x higher than normal
• heat attacks b/w 2-20 years of age

Question 21

true or false: autosomal dominant traits skip generations

Answer 21

false

Question 22

X-linked recessive traits have:

Answer 22

• a distinctive pattern of inheritance
• occur more frequently in males

Question 23

males with X-linked recessive traits are born to _________ mothers

Answer 23

obligate carrier

Question 24

are X-linked traits passed from father to son?

Answer 24

no

Question 25

what is one example of an X-linked recessive trait?

Answer 25

hemophilia A

Question 26

how have some heterozygous females been able to experience milder forms of hemophilia?

Answer 26

X chr inactivation

Question 27

X-linked dominant traits:

Answer 27

• appear in both males and females
• offspring with trait must have a parent displaying a trait
• affected men pass to all of their daughters but none of their sons
• affected heterozygous women pass to half of their daughters and half of their sons

Question 28

what is an example of an X-linked dominant trait?

Answer 28

hypophosphatemia (vitamin D resistant rickets - soft bones)

Question 29

Y-linked traits:

Answer 29

• only males are affected
• does not skip generations
• neither dominant or recessive