Chapter 14 Flashcards
1
Q
character
A
a heritable feature (ie flower color)
2
Q
trait
A
a variant of character, such as purple or white flowers
each carries two copies of a gene (one from mom, one from dad)
3
Q
alleles
A
alternative forms of genes (D, d)
4
Q
complete dominance
A
heterozygous phenotype same as that of homozygous dominant
PP, Pp = purple
5
Q
Incomplete dominance
A
heterozygous phenotype intermediate between the two homozygous phenotype
CRCW = Pink
6
Q
codominance
A
both phenotypes expressed in heterozygotes
IAIB
7
Q
Multiple alleles
A
in the whole population, some genes have more than two alleles
ABO blood group alleles - IA, IB, i
8
Q
Pleiotropy
A
one gene affects multiple phenotypic characters
ex. sickle-cell disease
9
Q
epistasis
A
the phenotypic expression of one gene affects that of another
(ex. Labradors have a gene to be brown (Bb), the next gene affects how much color is shown, ee at that gene will mean a yellow dog no matter what the first gene is)
10
Q
Polygenic inheritance
A
a single phenotypic character is affected by two or more genes
11
Q
antagonistic traits
A
one trait repels another
12
Q
geneotype
A
pair of alleles present in an individual
13
Q
capitalized traits
A
dominant phenotypes
14
Q
lowercase traits
A
recessive phenotypes
15
Q
hybridization
A
mating 2 contrasting true-bred organisms
16
Q
Heredity concepts
A
- Alternative versions of genes account for variations in inherited characters, whcih are now called alleles
- For each character an organism inherits 2 alleles, one from each parent, a genetic locus is actually represented twice
- If the 2 alleels at a locus differ, the dominant allele determines the organism’s appearance
- The Law of Segregation
17
Q
The Law of Segregation
A
the 2 alleles for a heritable character separate during gamete formation and end up in different gametes
it’s a mechanism of gene transmission
18
Q
gametogenesis
A
alleles segregate (in gamete formation)
19
Q
Punnett squares
A
show how traits can segregate and reunite
20
Q
test cross
A
allows us to determine genotype of unknown organism with dominant phenotype cross with homozygous recessive
21
Q
Law of Independent Assortment
A
when gametes form, each pair of heredity factors (alleles) separate independently of the other pairs
22
Q
Law of Probability
A
Multiplication rule (independent events)
addition rule (dependent events)
23
Q
Mendel’s Conclusions
A
- Genes are distinct entities that remain unchanged during crosses
- Each plant has two alleles of a gene
- Alleles segregate into gametes in equal proportions, each gamete got only one allele
- During gamete fusion, the numer of alleles was restored to two
*
24
Q
Relationship between dominance and phenotype
A
For any character, dominance/recessiveness relationships of alleles depend on the level at which we examine the phenotype
ex. Tay-Sachs disease (fatal; a dysfunctional enzyme causes an accumulation of lipids in brain)
- at organismal level, allele is recessive
- at biochemical level; phenotype (ie enzyme activity level) is incompletely dominant
- at the molecular level, the alleels are codominant
25
Polygenic traits
the combined interaction of many gene loci control most traits, often show continuous variation
ex. skin color in humans
26
Quantitative characters
those that vary in the population along a continuum
Quantitative variation usually indicates polygenic inheritance
27
Phenotype depends on genotype and...?
Phenotype also depends on environment
ex. Arctic Fox
28
Norm of Reaction
phenotypic range of a genotype influenced by the environment
29
Pedigree
a family tree that describes the interrelationships of parents and children across generations
Can be used to trace and describe inheritance patterns, predict phenotype of future offspring
30
Recessively inherited disorders
rr causes disease, Rr is unaffected individual (but is a **carrier**)
many genetic disorders are inherited in a recessive manner
can range from mild to life-threatening
31
Consanguineous mating
matings betwen close releatives
increase the chance of mating between 2 carriers of the same rare allele
32
Albinism
lakc of pigment in skin/hair
recessively inherited disorder
33
Cystic Fibrosis
Recessively inherited disorder
most common lethal genetic disease in U.S.
European descent
allele results in defective or absent chloride transport channels in plasma membrane leading to a buildup of chloride ions outside the cell
symptoms: mucus buildup in some, internal organs, and abnormal absorption of nutrients in small intestine
34
Sickle-Cell disease
a genetic disorder with evolutionary implications
African americants
caused by a substitution of a single amino acid in the hemoglobin protein in red blood cells
symptoms: physical weakness, pain, organ damage, and even paralysis
Heterozygotes are mostly healthy, restistant to malaria
35
Dominantly inherited disorders
dominant allels that cause a lethal disease are rare and arise by mutation
36
Achondroplasia
a form of dwarfism
dominantly inherited
37
Huntington's Disease
a late-onset lethal disease
a degenerative disease of the nervous system
dominantly inherited
38
Multifactorial disorders
many diseases have both genetic and environmental components
ex. heat disease, diabetes, alcoholism, mental illnesses, cancer
little is understood about the genetic contribution to most multifactorial diseases
39
a heritable feature (ie flower color)
character
40
a variant of character, such as purple or white flowers
each carries two copies of a gene (one from mom, one from dad)
trait
41
alternative forms of genes (D, d)
alleles
42
heterozygous phenotype same as that of homozygous dominant
PP, Pp = purple
complete dominance
43
heterozygous phenotype intermediate between the two homozygous phenotype
CRCW = Pink
Incomplete dominance
44
both phenotypes expressed in heterozygotes
IAIB
codominance
45
in the whole population, some genes have more than two alleles
ABO blood group alleles - IA, IB, i
Multiple alleles
46
one gene affects multiple phenotypic characters
ex. sickle-cell disease
Pleiotropy
47
the phenotypic expression of one gene affects that of another
(ex. Labradors have a gene to be brown (Bb), the next gene affects how much color is shown, ee at that gene will mean a yellow dog no matter what the first gene is)
epistasis
48
a single phenotypic character is affected by two or more genes
Polygenic inheritance
49
one trait repels another
antagonistic traits
50
pair of alleles present in an individual
geneotype
51
dominant phenotypes
capitalized traits
52
recessive phenotypes
lowercase traits
53
mating 2 contrasting true-bred organisms
hybridization
54
1. Alternative versions of genes account for variations in inherited characters, whcih are now called alleles
2. For each character an organism inherits 2 alleles, one from each parent, a genetic locus is actually represented twice
3. If the 2 alleels at a locus differ, the dominant allele determines the organism's appearance
4. The Law of Segregation
Heredity concepts
55
the 2 alleles for a heritable character separate during gamete formation and end up in different gametes
it's a mechanism of gene transmission
The Law of Segregation
56
alleles segregate (in gamete formation)
gametogenesis
57
show how traits can segregate and reunite
Punnett squares
58
allows us to determine genotype of unknown organism with dominant phenotype cross with homozygous recessive
test cross
59
when gametes form, each pair of heredity factors (alleles) separate independently of the other pairs
Law of Independent Assortment
60
Multiplication rule (independent events)
addition rule (dependent events)
Law of Probability
61
* Genes are distinct entities that remain unchanged during crosses
* Each plant has two alleles of a gene
* Alleles segregate into gametes in equal proportions, each gamete got only one allele
* During gamete fusion, the numer of alleles was restored to two
*
Mendel's Conclusions
62
For any character, dominance/recessiveness relationships of alleles depend on the level at which we examine the phenotype
ex. Tay-Sachs disease (fatal; a dysfunctional enzyme causes an accumulation of lipids in brain)
* at organismal level, allele is recessive
* at biochemical level; phenotype (ie enzyme activity level) is incompletely dominant
* at the molecular level, the alleels are codominant
Relationship between dominance and phenotype
63
the combined interaction of many gene loci control most traits, often show continuous variation
ex. skin color in humans
Polygenic traits
64
those that vary in the population along a continuum
Quantitative variation usually indicates polygenic inheritance
Quantitative characters
65
Phenotype also depends on environment
ex. Arctic Fox
Phenotype depends on genotype and...?
66
phenotypic range of a genotype influenced by the environment
Norm of Reaction
67
a family tree that describes the interrelationships of parents and children across generations
Can be used to trace and describe inheritance patterns, predict phenotype of future offspring
Pedigree
68
rr causes disease, Rr is unaffected individual (but is a **carrier**)
many genetic disorders are inherited in a recessive manner
can range from mild to life-threatening
Recessively inherited disorders
69
matings betwen close releatives
increase the chance of mating between 2 carriers of the same rare allele
Consanguineous mating
70
lakc of pigment in skin/hair
recessively inherited disorder
Albinism
71
Recessively inherited disorder
most common lethal genetic disease in U.S.
European descent
allele results in defective or absent chloride transport channels in plasma membrane leading to a buildup of chloride ions outside the cell
symptoms: mucus buildup in some, internal organs, and abnormal absorption of nutrients in small intestine
Cystic Fibrosis
72
a genetic disorder with evolutionary implications
African americants
caused by a substitution of a single amino acid in the hemoglobin protein in red blood cells
symptoms: physical weakness, pain, organ damage, and even paralysis
Heterozygotes are mostly healthy, restistant to malaria
Sickle-Cell disease
73
dominant allels that cause a lethal disease are rare and arise by mutation
Dominantly inherited disorders
74
a form of dwarfism
dominantly inherited
Achondroplasia
75
a late-onset lethal disease
a degenerative disease of the nervous system
dominantly inherited
Huntington's Disease
76
many diseases have both genetic and environmental components
ex. heat disease, diabetes, alcoholism, mental illnesses, cancer
little is understood about the genetic contribution to most multifactorial diseases
Multifactorial disorders
