Genetic Disease 8/23/05 R Lecture

Front 1

What is a karyotype?

Back 1

the set of chromosomes of a species. humans have 46.

Front 2

Meiosis 1 produces 2 ___cells non identical

Back 2

haploid!

Front 3

What is independent assortment?

Back 3

each pair of homologous chromosomes aligns independently of the pther pairs.

Front 4

What is the formula for independent assortment?

Back 4

2^n where "n" is the number of pairs of homologous chromosomes

Front 5

2 genes are _____ if they are on the same chromosome.

Back 5

linked

Front 6

2 genes are ______ if they are on different (non-homologous) chromosomes

Back 6

unlinked

Front 7

linked genes that are how far apart assort independently?

Back 7

50 map units or more

Front 8

What is crossing over

Back 8

swapping of DNA segments in Meiosis 1 btw non sister chromatids of homologous chromosomes.

Front 9

What do you call the area of contact btw crossing over?

Back 9

chiasmata.

Front 10

Who is big man on the human genome project?

Back 10

Francis Collins

Front 11

How far apart are 2 genes if they crossover 1% of the time? 10%? 50%?

Back 11

1 map unit, 10 map units, unlinked

Front 12

About how many crossovers occur during Meiotic division? How many pre chromosome?

Back 12

30-40

1-2

Front 13

What are Mendels 3 laws?

Back 13

USI
Unit inheritance-traits dtermined by genes which are inhreited as distinct units
Segregation-genes occur in pairs and each member separates from each other during meiosis
Independent assoprtment- unlinked genes assort independently

Front 14

What is a specific location on a chromosome?

Back 14

locus

Front 15

What are different forms of a gene at a given locus?

Back 15

alleles

Front 16

What is a phenotype?

Back 16

observed result of interaction btw genes and environment

Front 17

What are Mendelian diseases?

Back 17

Single gene defects

Front 18

Dominance/Recessive refer to ________ and not _____

Back 18

traits or phenotypes...not genes or alleles

Front 19

What is codominance?

Back 19

both of the alleles are expressed

Front 20

Hereditary colon cancer
Huntington disease and Familial hypercholsterolemia are types of what kind of inheritance?

Back 20

Autosomal dominant disorders

Front 21

What are the 4 criteria for autosomal dominance inheritance?

Back 21

1. trait in ever generation
2. trait transmitted to 1/2
3. Unaffected dont transmit
4. male and female equal likely of getting it

Front 22

What is the usual pattern of inheritance for rare autosomal recesive trait?

Back 22

Aa x Aa

Front 23

What is the usual pattern of inheritance for rare autosomal trait?

Back 23

Aa x aa
abnormal x normal

Front 24

The probablity joint of ocurrences or 2 or more independent events is

Back 24

product of their separate probablities.

Front 25

What is the binomial formula?

Back 25

(p+q)^n
p=probablity of one event
q=probability of alternate(s)(girl)
n=number of independent events (#kids)

Front 26

____can produce an affected child from 2 seemingly unaffected parents

Back 26

decreased penetrance

Front 27

Penetrance is _____ or _____

Back 27

all or none

Front 28

If allele for dominant trait expressed they are_______, if no expression they are ___

Back 28

penetrant
nonpenetrant

Front 29

If 100 people have an allele but only 73 express it, we say______

Back 29

73% penetrance

Front 30

the DEGREE of expression of a trait in population refers to ________

Back 30

variable expressivity

Front 31

What is pleiotropy and what is it found with?

Back 31

multiple secondary phenotypic effects from the primary genetic defect. Variable expressivity

Front 32

Typical age of onset of phenylketonuria, galactosemia, cystic fibrosis

Back 32

soon after birth

Front 33

typical onset age for Tay-Sachs, Duchenne, muscular dystrophy

Back 33

During first year of life

Front 34

Typical onset age for hereditary juvenile glaucoma

Back 34

young adulthood

Front 35

Typical disease with variable onset ages

Back 35

Diabetes mellitus
Huntington's chorea

Front 36

_____ is when different mutations give rise to similar phenotypes

Back 36

Genetic heterogeneity

Front 37

______ are different mutations at the same locus

Back 37

allelic heterogeneity

Front 38

_____ are mutations at different loci

Back 38

locus heterogeneity

Front 39

_______ are environmentally produced traits that mimic eentic defects such as iodine deficiency goiter

Back 39

phenocopies

Front 40

____refers to traits that have a genetic component but must have an environmental trigger.

Back 40

genetic predisposition

Front 41

a ________ is an autosomally transmitted but expressed ONLY in one sex, sex hormones regulate geen expression, and an example is precocious puberty

Back 41

Sex-limited

Front 42

______ is autosomally transmitted but expressed differently in males and females, sex hormones affect, example is male pattern baldness

Back 42

sex-influenced

Front 43

________ is the differential expression of alleles depending on parent of origin

Back 43

genomic imprinting

Front 44

___refers to traits whose expression has earlier age onset as passed from generation to generation
Huntington's disease, CAG repeats

Back 44

anticipation

Front 45

Hyperlipidemias type I and II
most enzyme deficiencies
cystic fibrosis and Tay-sachs are all examples of what kind of inheritance

Back 45

Autosomal recessive

Front 46

What are the 4 criteria for Autosomal recessive inheritance?

Back 46

1. only in sibs, not parents/offspring
2. 1/4 risk
3. Parents of affected may be consanguineous
4. Males and Females equal

Front 47

____ is the more rare a disease, the more likely the mating of close relatives

Back 47

consanguinity

Front 48

In _______ heterozygotes have about 1/2 the normal activity of hexose-amindase

Back 48

Tay-Sachs

Front 49

______carriers can be detected by Hb electrophoresis

Back 49

Sickle Cell

Front 50

Males are ___ for X-linked traits

Back 50

hemizygous

Front 51

Hemophilia A, Duchenne Musc Dys, and G6PD are examples of what type of inheritance?

Back 51

X-linked recessive

Front 52

What are 4 criteria for X linked recessive?

Back 52

1. much higher in males
2. Passed from affected man to through all his daughters to half their sons
3. Never from Father to son
4. May be from carrier females, the affected males related to each thru females

Front 53

Apparant male to males transmission of X linked recessive from father to son can occur when?

Back 53

the allele is very common

Front 54

Hypophoshphatemia (Vit D rickets) and Ornithine transcarbamoylase deficiency are examples of what type of inheritance?

Back 54

X linked dominance

Front 55

What are the 3 criteria for X linked dominant?

Back 55

1. Affected males give to all daughters and no sons
2. Affected females homo =transmit to all children, hetro=pass to 1/2
3.in rare Xlinked dom, females twice as common but in milder form.