Module 3 Unit 2: Variations in Gene Expression

Question 1

The Traits that we have learned from the previous units are considered?

Answer 1

qualitative traits

Question 2

These traits are controlled by genes with a cumulative effect such that the phenotypes show small, gradual differences.

Answer 2

quantitative traits

Question 3

Is an interplay between genetic makeup and environmental factors.

Answer 3

phenotypic variations

Question 4

They are influenced by the type, number, and inheritance pattern of the gene/s.

Answer 4

phenotypic variations

Question 5

Refers to the proportion of a population that will exhibit a particular trait if the allele is found in their genotype.

Answer 5

Penetrance or Quantitative Concept

Question 6

100% of all individuals with the same allele in their genotype expresses the trait

Answer 6

Complete Penetrance

Question 7

Not all individuals with the same allele in their genotype expresses the trait.

This is the type of penetrance exhibited by incomplete dominance, codominance, gene interaction, and epistasis.

Answer 7

Incomplete / Reduced Penetrance

Question 8

Refers to the degree of expression of a penetrant gene

Answer 8

Expressivity / Qualitative Concept

Question 9

Expressivity is dependent on?

Answer 9

penetrance

Question 10

A trait must be __________ for expressivity to be assessed.

Answer 10

penetrant

Question 11

Is a trait that is non- genetic

Answer 11

Phenocopy

Question 12

Is due to an environmental factor but mimics a phenotype.

Answer 12

Phenocopy

Question 13

These two terms refer to the expression of traits by members of monozygotic twins

Answer 13

Concordance and Discordance

Question 14

If both monozygotic twins exhibit a trait, the trait is called?

Answer 14

concordant

Question 15

It means that the trait has a genetic basis

Answer 15

Concordance

Question 16

True or False:
Since monozygotic twins have exactly the same genetic composition, a genetic trait present in one member is also present in the other.

Answer 16

True

Question 17

If a trait is exhibited by one member of a monozygotic twin but is not exhibited by the other member, the trait is?

Answer 17

discordant

Question 18

If both members of a monozygotic twin were born deaf, then the trait most likely has a genetic basis, thus?

Answer 18

concordant

Question 19

If only one member of the monozygotic twin is deaf, the condition cannot be genetic, thus considered?

Answer 19

discordant

Question 20

Quantitative traits are governed by multiple genes thus referred to as?

Answer 20

polygenic traits

Question 21

Each allele of each gene interacts ______ and contribute to the expression of that particular trait

Answer 21

Additively

Question 22

Regions of the DNA that contribute to a quantitative trait are collectively referred to as ________ and located in different chromosomes

Answer 22

quantitative trait loci (QTL)

Question 23

Most regions are protein-coding regions called ______, while some are __________ (thus not called genes) but still contribute to the trait

Answer 23

1. genes
2. regulatory regions

Question 24

Quantitative traits are affected by both the DNA and the environment, thus called?

Answer 24

multifactorial

Question 25

Is considerably variable because of the small continuous differences

Answer 25

polygenic trait

Question 26

Is determined by the genes of an individual and the environment

Answer 26

Phenotypic Variance

Question 27

Phenotypic Variance Formula

Answer 27

VP = VG + VE

Question 28

Is determined by incomplete dominance, complete dominance, and gene interactions and epistasis

Answer 28

Genotypic variance

Question 29

Genotypic variance Formula

Answer 29

VG = VA + VD + VI

Question 30

Differences in the phenotype observed in a population

Answer 30

phenotypic variance

Question 31

Differences observed in a population that is due ONLY to the genotype

Answer 31

genotypic variance

Question 32

Differences observed in a population that is due ONLY to environmental factors

Answer 32

environmental variance

Question 33

Refers to the variance due to the total quantitative effects of each allele in a polygene

Answer 33

Additive Variance

Question 34

It is also known as the breeding value because it represents the worth of the genes to the next generation; how much would the genes contribute to the phenotype of the offspring

Answer 34

Additive Variance

Question 35

Refers to some genes that act on the same characteristic exhibit complete dominance

Answer 35

dominance variance

Question 36

Some genes that act on the same characteristic exhibit gene interactions

Answer 36

interaction variance

Question 37

Refers to the variance due to the interaction between genes at different loci.

Answer 37

interaction variance

Question 38

Refers to the percentage of phenotypic variation that is due to genotypic variations

Answer 38

Heritability

Question 39

The proportion of the phenotypic variation due to ALL the genetic factors

Answer 39

Broad Sense Heritability (H2)

Question 40

Broad Sense Heritability (H2) Formula

Answer 40

H^2= Vg/Vp x 100

Question 41

Proportion of the phenotypic variation based on the additive genetic variance

Answer 41

Narrow Sense Heritability (h2)

Question 42

It is a measure of how likely an offspring will resemble its parents

Answer 42

Narrow Sense Heritability (h2)

Question 43

It is important in determining how a trait will respond to selection

Answer 43

Narrow Sense Heritability (h2)

Question 44

Extremely important for breeding because it deals with traits that are of value for the next generation

Answer 44

Narrow Sense Heritability (h2)

Question 45

Narrow Sense Heritability (h2) Formula:

Answer 45

h2 = Va/Vp x 100

Question 46

If H2 = 0?

Answer 46

The phenotypic variance is due to environmental factors only

Question 47

If H2 = 100%?

Answer 47

The phenotypic variance is due to the genotype only

Question 48

If H2> 0?

Answer 48

the phenotypic variance is partly due to genotype

Question 49

If h2 = 0?

Answer 49

the phenotypic variance is due to environmental factors only

Question 50

If h2 =100%

Answer 50

the phenotypic variance is due to the additive genetic variance

Question 51

If h2> 0

Answer 51

the phenotypic variance is partly due to genotype

Question 52

Comes from the word “epi” which means outside and “genetics” referring to the genes

Answer 52

Epigenetics

Question 53

Refers to the study of factors that alter gene expression without changing the DNA nucleotide sequence.

Answer 53

Epigenetics

Question 53

Refers to the study of factors that alter gene expression without changing the DNA nucleotide sequence.

Answer 53

Epigenetics

Question 54

Molecules that alter gene expression either promote or prevent the transcription of genes. All these “gene expression-altering” molecules taken together make up the entire ______.

Answer 54

Epigenome

Question 55

T or F: Most epigenetic changes are irreversible.

Answer 55

True

Question 56

All ________ daughter cells inherit the change, thus remain throughout the lifetime of the organism.

Answer 56

mitotic

Question 57

Can occur if the epigenetic change is retained during gametogenesis, that is, the gametes still have the epigenetic change

Answer 57

Transgenerational epigenetic inheritance

Question 58

Functions to turn off gene expression

Answer 58

DNA methylation

Question 59

It prevents gene transcription, thus involved in gene silencing

Answer 59

DNA methylation

Question 60

T or F: Histone proteins have tails that stick out of the nucleosome.

Answer 60

Histone modification

Question 61

Histone proteins have tails that are easily accessible for epigenetic modifications that alter the packaging of the DNA, to either promote or prevent transcription. This process is called?

Answer 61

Histone modification

Question 62

Non-coding RNAs (ncRNAs) are transcribed by the DNA but not translated to proteins

Answer 62

Gene Silencing by ncRNA

Question 63

Aside from differentiation, epigenetic processes may also occur due to environmental factors that could trigger DNA methylation, histone modifications, and miRNA post-translational modification

Answer 63

Epigenetic Factors

Question 64

One allele (paramutagenic) will prevent the expression of another allele (paramutable). This is called?

Answer 64

Paramutation

Question 65

What is the rule in paramutation?

Answer 65

As long as the paramutagenic a is present in the genotype, the paramutable A is not expressed, thus the color of the corn kernel becomes light.

Question 66

One allele is marked via DNA methylation for silencing, while the other allele is expressed.

Answer 66

Genomic Imprinting

Question 67

Balances the expression of the X-linked genes in males and females

Answer 67

Dosage Compensation