Genes and patterns of inheritance

Question 1

Genes and inheritance

What plant did Gregor Mendel use

Answer 1

Garden pea

Question 2

Genes and inheritance

Traits Mendel observed

Answer 2

Flower colour

Flower position

Seed colour

Seed shape

Pod shape

Pod colour

Height

Question 3

Genes and inheritance

Single factor cross

Answer 3

When an experimenter looks at only one trait

Question 4

Genes and inheritance

P generation

Answer 4

True breeding parents

Question 5

Genes and inheritance

F1 generation

Answer 5

Offspring of P cross

Question 6

Genes and inheritance

P cross

Answer 6

When you cross true bredding parents (P generation)

Question 7

Genes and inheritance

F2 generation

Answer 7

Result of allowing F1 generation to self fertilise

Question 8

Genes and inheritance

Dominant trait

Answer 8

Displayed trait

Question 9

Genes and inheritance

Recessive trait

Answer 9

Trait that is masked by the dominant trait

Question 10

Genes and inheritance

Gene

Answer 10

Sequence of DNA

Specific area of a specific chromosome

Codes for one of an organisms traits

Question 11

Genes and inheritance

Allele

Answer 11

Variation of a gene

Every individual has 2 alleles for every trait

Can be dominant or recessive

Question 12

Genes and inheritance

Medel’s Law of segregation

Answer 12

2 copies of a gene seperate from each other during the transmission from parent to offspring

Question 13

Genes and inheritance

Segregation of alleles

Answer 13

The two copies of allels carried by the parent seperate from each other

Each sperm/egg carries only 1 allele

Question 14

Genes and inheritance

The ratio of traits Medel found in F1

Answer 14

3:1

Question 15

Genes and inheritance

Genotype

Answer 15

Genetic composition of an individual

Homozygous or heterozygous

Question 16

Genes and inheritance

Homozygous

Answer 16

Carry two alleles for a gene that are the identical

Question 17

Genes and inheritance

Heterzygous

Answer 17

Carry two alleles for a gene that are different

Question 18

Genes and inheritance

Phenotype

Answer 18

Characteristics of an organism resulting from the expression of its genes

Question 19

Genes and inheritance

Method for predicting the outcome of crosses

Answer 19

Punnett square

Question 20

Genes and inheritance

Test cross

Answer 20

Used to determine an individuals genotype

Cross with a homozygous recessive individual

Question 21

What is the unknown genotype if the

Test cross results in offspring that all have the dominant trait

Answer 21

Homozygous for the dominant trait

Question 22

What is the unknown genotype if the

Test cross results in offspring where half have the dominant trait and half have the recessive trait

Answer 22

Heterozygous

Question 23

What is the unknown genotype if the

Test cross results in offspring that all have the recessive trait

Answer 23

Homozygous for the recessive trait

Question 24

Genes and inheritance

Two factor cross

Answer 24

Follow inheritance of 2 different traits

Can either be linked or independant

Question 25

# Genes and inheritance Two-factor cross results in a 3:1 ratio of offspring characteristics. How are the genes assorted

Answer 25

Linked assortment

Question 26

# Genes and inheritance Two-factor cross results in a 9:3:3:1 ratio of offspring characteristics. How are the genes assorted

Answer 26

Independant assortment

Question 27

# Genes and inheritance Law of independant assortment

Answer 27

Alleles of different genes sort independantly of each other during gamete formation

Question 28

# Genes and inheritance Locus

Answer 28

Physical location of a gene on a chromosome

Question 29

# Genes and inheritance Wild type allele

Answer 29

Prevelant allele in a population Encodes a protein made in the proper amount and functions normally

Question 30

# Genes and inheritance Mutant alleles

Answer 30

Altered by a mutation Tend to be rare in natural populations Almost always unable to express a funtional protein

Question 31

# Genes and inheritance Simple dominance

Answer 31

Recessive allele doesn't affect the phenotype of a heterozygous individual Dominant allele masks it

Question 32

# Genes and inheritance Reasons for Mendel using the plant he did

Answer 32

Many different characteristics/traits Self-fertilising Easy to make crosses with

Question 33

# Genes and inheritance Imcomplete dominance

Answer 33

Heterzygous offspring can show an intemdiate trait to the phenotypes of parents Neither allele is dominant 50% of normal protein isn't enough

Question 34

# Genes and inheritance Codominance

Answer 34

Heterzygote express both alleles simultaneously

Question 35

# Genes and inheritance Pleitropy

Answer 35

Mutation to a single gene can have multiple effects to an individuals phenotype

Question 36

# Genes and inheritance Plant used to discover incomplete dominance

Answer 36

Four-o'clock plant

Question 37

# Genes and inheritance X linked genes and disorders

Answer 37

Males hemizygous for X-linked genes X-linked recessive traits more likely in males

Question 38

# Genes and inheritance Hemizygous

Answer 38

Only one copy of gene is present

Question 39

# Genes and inheritance X-linked genes

Answer 39

Genes found on the X chromosome but not the Y

Question 40

# Genes and inheritance Norm of reactions

Answer 40

Effects of environmental variation of phenotype For example, plants in better soil grow bigger

Question 41

# Genes and inheritance Gene interaction

Answer 41

When a single charecteristic is controlled by 2 or more genes

Question 42

# Genes and inheritance Epistasis

Answer 42

Gene interactions When the alleles of one gene can mask the expression of alleles from another gene Often because 2 or more different proteins involved in a single cellular function

Question 43

# Genes and inheritance Bateson and Punnett Early 1900s

Answer 43

Crossed 2 varieties of white flowered pea F1 had all purple flowers - *Unexpected* F2 had a 9:7 ratio of purple:white flowers Concluded must be 2 genes involved in flower colour

Question 44

# Genes and inheritance Discrete traits

Answer 44

Clearly defined phenotypic varients One or the other trait

Question 45

# Genes and inheritance Quantitative traits

Answer 45

Show contineous variation over a range of phenotypes Usually polygenic Environment plays a role

Question 46

# Genes and inheritance Example of discrete trait

Answer 46

White or purple flowers Red or white eyes

Question 47

# Genes and inheritance Examples of quantitative traits

Answer 47

Height Hair colour Skin colour Number of apples on a tree

Question 48

# Genes and inheritance Polygenic

Answer 48

Several or many genes contribute to the outcome of the trait Many contribute in an additive way

Question 49

# Genes and inheritance Gene linkage

Answer 49

When 2 genes are close on the same chromosome Tend to be transmitted as a single unit Don't tend to follow the law of independant assortment

Question 50

# Genes and inheritance Recombinants

Answer 50

Normally small number of total offspring Don't have the traits of parental generation

Question 51

# Genes and inheritance Nonrecombinants

Answer 51

Combination of traits has not changed from the parental generation

Question 52

# Genes and inheritance Stage of meiosis where chromsomes can be echanged

Answer 52

Crossing over

Question 53

# Genes and inheritance What effects the likelihood of crossing over

Answer 53

Distance between two genes More likely in genes that are far apart

Question 54

# Genes and inheritance Recombination frequency

Answer 54

Frequency of crossing over between two genes Used to work out the distance between them

Question 55

# Genes and inheritance Gentic linkage mapping/gene mapping/chromosome mapping

Answer 55

Used to determine linear order of genes that are linked to each other along the same chromosome

Question 56

# Genes and inheritance Genetic map

Answer 56

Chart that shows relative locations of genes on a chromosome Estimated by how likely a crossover will occur between linked genes

Question 57

# Genes and inheritance Map units

Answer 57

Units of distance between two genes Equivalent to 1% recombination frequency

Question 58

# Genes and inheritance Test crosses and recombination frequency

Answer 58

Do a two-test cross If this produces lots of recombinants you can conclude that the two genes are far apart Ver few recombinants - close together

Question 59

# Genes and inheritance What can you conclude from a test cross where there are a lot of recombinant offspring

Answer 59

The genes in question are far apart on the chromosome

Question 60

# Genes and inheritance Map distance =

Answer 60

Number of recombinants/\total number of offspring Multiply answer by 100