test 2: non-mendelian genetics

Question 1

pedigree

Answer 1

inheritance within a family group

• analyzed to determine carriers for a disease
• tracks disease or morphological traits in families

Question 2

males are represented by what shape in a pedigree?

Answer 2

square

Question 3

females are represented by which shape in a pedigree?

Answer 3

circle

Question 4

autosomal recessive

Answer 4

can be hidden and skip generations

Question 5

autosomal dominant inheritance

Answer 5

each affected child has an affected parent

Question 6

simple autosomal recessive inheritance

Answer 6

• trait determined by one gene on an autosome
• only expressed by homozygous recessive individuals
• certain diseases found in specific populations
• skips generations // equal chance male or female
• both parents have to be carriers to pass on disease
• homozygous recessive NOT carriers

Question 7

carrier

Answer 7

keeps allele in population but doesn’t exhibit the disease

Question 8

exs of autosomal recessive

Answer 8

cystic fibrosis, tay sach’s

Question 9

cystic fibrosis

Answer 9

• 1 in 20 white north americans are carriers
• deadly: cannot reproduce
• respiratory disease
• determined through genetic analysis and medical symptoms
• all children born in north american are screened

Question 10

tay sach’s

Answer 10

carriers: eastern european jews and french canadians

- brain swelling (enzyme doesn’t work), death by age 5

Question 11

sickle cell anemia

Answer 11

• 1 in 4 black people in central Africa are carriers
• carriers more likely to survive malaria
• susceptible to infections, fever, severe pain in chest and extremities
• can’t deal with overexertion, high altitude, or respiratory illnesses

Question 12

albinism

Answer 12

• 1 in 70 from most populations are carriers
• social/sun are the only risk factors
• genetic condition which strikes all animal species (not just humans): may inhibit camouflage

Question 13

simple autosomal dominant inheritance

Answer 13

• 1 gene site
• autosomal not gender related
• trait produced with at least one dominant allele
• most inherited traits are not fatal

Question 14

simple autosomal dominant inheritances - diseases

Answer 14

dwarfism

huntington’s disease

Question 15

huntington’s disease

Answer 15

• affects individuals 40-50 years old
• fatal disease (only takes one dominant allele)
• two dominant alleles is very rare but they do survive
• disease manifests itself after 40 (too late to not pass it on)
• neuromuscular degeneration

Question 16

what do both dwarfism and huntington’s display?

Answer 16

double dominance

Question 17

double dominance in dwarfism

Answer 17

deadly, baby survives a few days

Question 18

double dominance in huntington’s

Answer 18

very rare, usually a miscarriage

Question 19

how does one inherit a recessive trait?

Answer 19

• both parents must have allele

- kept in population because being heterozygous is not disagvantageous (carriers)

Question 20

how does one inherit a dominant trait?

Answer 20

• one parent must have allele

- if allele gives something bad, population will be purged of allele (dies out) - EXCEPTION HUNTINGTONS

Question 21

sex linked recessive inheritance

Answer 21

• on the x or y
• only looking at x
• trait is recessive and on x, increase rate of males express
• y: few alleles

Question 22

sex linked recessive inheritance examples

Answer 22

colour blindness, hemophilia

Question 23

x-inactivation

Answer 23

• female mammals don’t use both x’s
• as embryo: 1 X in each cell becomes inactive and is re-activated later only in ovaries
• inactive x coils up into barr body
• choice of x used is not random
• females are mosaics

Question 24

incomplete dominance

Answer 24

• offspring have an appearance somewhere between phenotypes of the two parents; “blending of the phenotypes”
• ex: red allele + white allele = red and white OR pink

Question 25

new heterozygous phenotypic ratio

Answer 25

incomplete = 1 : 2 : 1

Question 26

codominance (blood type)

Answer 26

• many genes in populations can exist in more than one more

Question 27

blood types

Answer 27

• 2 carbohydrates (A&B) found on surface of blood cell

- person can have one or the other (A or B), both (AB), or neither (O)

Question 28

blood antigens

Answer 28

• outside of blood cell has marker protein (antigen)
• antibodies are produced in the blood serum against foreign antigens
• antibodies bind to the “bad” blood and cause it to clump (deadly)
• careful with transfusions

Question 29

why must blood tranfusions be a certain weight?

Answer 29

• body will react to blood cells with tags they don’t recognize
• won’t react to O (no tags) = universal donor

Question 30

+/- blood types are extra tags

Answer 30

RH tag (directly inherited, if one parent has it, you must have it)

Question 31

Rh-

Answer 31

lacks antigen

Question 32

Rh+

Answer 32

has the antigen

Question 33

medical problems with Rh+/-

Answer 33

if mother is Rh- and fetus is Rh+ (from dad)

• small amounts of blood are transferred during childbirth
• mother can produce antibodies against the Rh+ factor
• next pregnancy: can kill the child or damage the blood supply system (hemolytic disease)
• prevention: RhoGam (destroys Rh+ antigens: prevents mother from producing any Rh antibodies) - works for short term (hurts immune system in the long run)

Question 34

epistasis

Answer 34

• a gene at one location affects the phenotypic expression of a gene at another locus
• there are many genes whose sole function is to turn on and off other genes

Question 35

pleiotrophy

Answer 35

genes have multi phenotypic effects (1 gene = multiple traits)

Question 36

polygenic inheritance

Answer 36

• some traits are not “either-or”
• 2 or more genes affect a single phenotype
  ex: human height, eye color, skin color
• these traits are called qualitative traits
• opposite of pleiotrophy (1 gene affects many phenotypes)
• multiple genes working together = one trait

Question 37

multifactorial inheritance

Answer 37

more than one genetic factor that controls it and it is influenced by environment (ex: the womb)

• root basis is genetic so it tends to run in families
• involves polygenic
  ex: human height interacts with nutrition; heart disease interacts with lifestyle

Question 38

extranuclear inheritance

Answer 38

• mitochondria and chloroplasts that carry their own DNA and replicate themselves (maternal)
• used for studies that involve tracing species and individuals in family trees or orgins of groups; also criminal cases