Chapter 6: Pedigree Analysis

Question 1

Pedigree

Answer 1

a pictorial representation of a family history that outlines the inheritance of one or more characteristics

Question 2

consanguinity

Answer 2

mating between closely related people

Question 3

proband

Answer 3

the person from who the pedigree is initiated

Question 4

genetic mosaic

Answer 4

condition in which regions of tissue within a single individual have different chromosome constitutions

Question 5

dizygotic twins

Answer 5

non identical twins; arise when two separate eggs are fertilized by two different sperm producing two distinct zygotes
- on average share on 50% of their genes like any pair of siblings does

Question 6

monozyotic twins

Answer 6

identical twins; when a single egg fertilized by a single sperm splits early in development into two separate embryos.
- are genetically identical and share 100% of their genes

Question 7

concordance trait

Answer 7

the percentage of twins pairs that are concordant for a trait. (the trait shared by both members of a twin pair)
- concordant meaning both members of a twin pair have a trait
- genetically influenced traits should exhibit higher concordance in monozygotic twins

Question 8

ultrasoundography

Answer 8

high frequency sound is used beamed into the uterus and waves bounce back resulting in picture formation.

Question 9

aminocentesis

Answer 9

procedure for obtaining a sample of amniotic fluid from the uterus of a pregnant woman

Question 10

chorionic villus sampling (CVS)

Answer 10

a small piece of the chorion (outer layer of the placenta) is removed from a pregnant woman through a high suction catheter.

Question 11

karyotype

Answer 11

a complete set of chromosomes possessed by an organism through a picture of a complete set of metaphase chromosomes.

Question 12

Autosomal Recessive

Answer 12

Observed Patterns:
- 2 unaffected offspring can have affected offspring
- both male and female offspring affected at similar frequencies
- tends to skip generations
- both parents hetero, 1/4 offspring will be affected

Question 13

examples of autosomal recessive disorders

Answer 13

1. cystic fibrosis
2. Sickle cell Anemia
3. Tay-Sachs disease

Question 14

Autosomal dominant

Answer 14

• affected individuals have at least one affected parent
• affected parents of either sex can pass on to offspring of either sex
• does not skip generations
• (affected hetero parent 1) Aa x (unaffected parent 2) aa , 1/2 of children will be affected

Question 15

Sex-linked Recessive

Answer 15

• unaffected parents can have affected offspring
• passed from unaffected female to affected male to unaffected female
• males affected more frequently than females
• transmitted from mothers to sons

Question 16

sex-linked dominant

Answer 16

• affected offspring come from affected parents
• appear in males and females but appear more frequently in females
• males can pass only to daughters
• females pass to children of either sex

Question 17

Y-linked trait

Answer 17

• only males have it
• pass to all of sons, none of daughters

Question 18

mitochondrial mutation

Answer 18

mothers always pass on while fathers never pass on

Question 19

cytoplasmic inheritance

Answer 19

• inherited through the egg not through sperm or polled
• mutant females means all mutant progeny
• mutant male means no mutant progeny

Question 20

Genetic Information Nondiscrimination Act (GINA)

Answer 20

Prohibits health insurers from using genetic information in decisions about health insurance and coverage rates.