extensions to Mendel's laws

Question 0

medels law 1? and 2?

Answer 0

1-traits segregate

2-characters independently assort

Question 1

Mendel’s Laws= ___________ __________

Answer 1

Mendelian inheritance

Question 2

• most prevalent alleles
• one or several (genetic polymorphism)
• typically code for properly functioning protein

Answer 2

wild type

Question 3

• uncommon alleles
• typically functioning protein
• often recessive (not always tho)

Answer 3

mutant alleles

Question 4

why are mutant alleles usually recessive?

Answer 4

• genes encode for proteins
• proteins have critical function
• mutant genotype leads to defective protein
• THEREFORE; heterozygotes have one allele that produces functioning protein (often, one wild allele is enough)

Question 5

-typically associated with gene mutation (defective protein)

Answer 5

recessive human disease

Question 6

• protein affected: hexosaminidase A
• function affected: lipid metabolism
• symptoms: paralysis, blindness, early death

Answer 6

Tay-Sachs Disease

Question 7

DOMINANT MUTANT ALLELE EXCEPTIONS:

-one functioning gene copy is not enough to produce wild-type phenotype?

Answer 7

haploinsufficiency

Question 8

DOMINANT MUTANT ALLELE EXCEPTIONS:

-mutation results in protein that counteracts wild-type?

Answer 8

dominant-negative mutations

Question 9

DOMINANT MUTANT ALLELE EXCEPTIONS:

• mutation gives protein new/abnormal function
• can be associated with too much protein expression?

Answer 9

gain of function mutation

Question 10

heterozygote results in mutant (not wild) phenotype

ex: polydactyly (having 6 fingers)

Answer 10

haploinsufficiency

Question 11

mutant protein adversely affects the wild-type

-often, mutant protein combines with wild protein, thereby altering or neg function

Answer 11

dominant-neg mutations

Question 12

GTPase Ras – S17N allele <—- what is this?

what does S17N do?

Answer 12

how cells communicate with each other
-cell transmission

-S17N blocks acivators
don’t activate effectors

Question 13

• Heterozygous phenotype indermediate
• dom allele (produces protein critical to red pigment)
• Recessive allele (produces non-functional protein)
• Heterozygotes produce intermediate pigment concentration

Answer 13

incomplete dominance

Question 14

when a genotype doesn’t result in expected phenotype.

how?

Answer 14

incomplete penetrance

-enviroment, modifier genes (gene affecting the expression of another)

Question 15

when heterozygotes have greater fitness than homozygotes ..

Answer 15

overdominance/ heterozygote advantage

Question 16

what is fitness?

Answer 16

ability to survive and reproduce and pass its genes on more.

Question 17

many genes have several alleles..

-__________ ___________ still have alleles per locus

Answer 17

diploid eukaryotes

Question 18

• diff. genotype, same protein
• multiple DNA combination codes for same amino acid
• proteins are made of amino acids

Answer 18

diff. alleles can code for same protein

Question 19

two pigments produced

-Eumelanin (blk) and Phaeomelanin (oragne/yellow)

Answer 19

coat color gene encodes tyrosinase, enzyme in Melanin production

Question 20

both alleles expressed in heterozygotes

-blood types

Answer 20

Codominance

Question 21

review slides in powerpoint

Answer 21

…

Question 22

X-linked recessive mutations

ex: Duchenne Muscular Dystrophy

Answer 22

gene encodes dystrophin protein

-muscle cell structural support

Question 23

reciprocal crosses to ID X-linked Genes:

Answer 23

male unaffected x Female affected

Male affected x Female unaffected

Question 24

associated with male traits in mammals - 70-300 genes on Y - 900-1200 genes on X * uncommon

Answer 24

Y-linkage

Question 25

some genes are located on both X&Y chromosomes | -they are inherited in the same manner as autosomal genes

Answer 25

pseudoautosomal inheritance

Question 26

Trait is dominate in one sex, recessive in other - often in heterozygotes only ex: baldness ...?

Answer 26

sex-influenced inheritance - affected by testosterone - gene produces protein that converts T to DHT - DHT affects expression of many genes, including those affecting hair growth

Question 27

- autosomal or X-linked - ex: egg-producing organs only in females. - leads to sexual dimorphism (characters phenotype differences btween sexes)

Answer 27

sex-linked inheritance

Question 28

Lethal Alleles typically result in __________ and are usually __________. **occur in __________ ________ (those required for survival, 1/3 of all genes).

Answer 28

death, recessive | essential genes

Question 29

__________ __________ :many cause death very early in development bc they affect basic genes like the ones that tell your cells to divide.

Answer 29

lethal alleles

Question 30

- Dominant allele - Nervous sys. degeneration late in life - age of onset= 30-50

Answer 30

huntington's disease

Question 31

affected by enviroment | -often tied to temp. (proteins are affected by temp.)

Answer 31

Conditional lethal alleles

Question 32

- a proportion of affected individuals die, not all - can be associated with enviroment, gene interactions - white eye allele in fruit flies is ___________.

Answer 32

semilethal alleles

Question 33

- single gene affects multiple traits. - most genes are pleiotrophic ex: cystic fibrosis... explain

Answer 33

pleiotrophy - gene encodes cystic fibrosis transmembrane conductance factor - regulates ionic balance of cells

Question 34

- expression of the same gene in diff. cell types may have diff. effects - expression of the same gene at diff.stages of dev. may have diff. effects - expression of one gene affects multiple cellular functions(depending on where the cells goes)

Answer 34

pleiotrophy mechanisms