Genetic Linkage & mapping in eukaryotes 4

Question 1

Synteny

Answer 1

Two or more genes are located on the same chromosoome (physically linked)

Question 2

Genetic linkage

Answer 2

Genes that are close to each other tend to transmitt together as linked genes

Question 3

Genes on the same chromosome that are close to each other are ________________

Answer 3

Physically linked (Can’t independently assort)

Question 4

When genes on the same chromosome are _____________ then independent assortment can happen

Answer 4

Far apart

Question 5

In an 9:3:3:1 ratio how many offsprings will have the parental phenotype?

Answer 5

10 ( 9 will have the dominant trait & 1 will have the recessive trait)

Question 6

In ______________ the domiant trait will show the most in a data and then the recessive trait will be the second most to show in a data

Answer 6

Linked genes

Question 7

In _______________ genes the dominant trait will show the most in a dat & the recessive trait will show the least (9 domiant, 1 recessive) (9:3:3:1)

Answer 7

Independent assorted

Question 8

If linked genes are ___________ independent assortment will occur but the rate of independent assortment will depend on the distance apart

Answer 8

Far Apart

Question 9

Independent assortment of linked genes leads to crossing over which results in ________________

Answer 9

Recombinant geneotypes & offsprings

Question 10

Crossing over occurs in ___________ where the homologous sister chromatids pairs up & each one switch a fragment with each other

Answer 10

Prophase 1 in meiosis 1

Question 11

Recombinants

Answer 11

Combinations of genotypes that are different from the parents

Question 12

Why doesn’t crossing over occur within sister chromatids?

Answer 12

Because sister chromatids are identical to each other therefore won’t have any genetic diversity

Question 13

The likelihood of crossing over between two genes depends on the ________________

Answer 13

Distance between them

Question 14

If two genes are __________ the crossing over will occur

Answer 14

Far apart

Question 15

If two genes are _________ then crossing over wont happen

Answer 15

Close together

Question 16

A _____________ can be used to determin if two genes are linked or not

Answer 16

Chi square test

Question 17

If the chi sqaure value is ______ then can agree that the genes are not linked & they are indenpendly assortted

Answer 17

Low

Question 18

What is the null hypothesis when determine if genes are linked or not?

Answer 18

That they are not linked & assort independly

Question 19

If the chi square test is ______ then have to reject the null hypothesis & agree that the genes are linked

Answer 19

High

Question 20

Genetic mapping

Answer 20

Determines the linear order & distance of seperation among genes that are linked to each other on the same chromosome

Question 21

The goal of a test cross is what?

Answer 21

To determine if recombination has occured

Question 22

What is the equation for map distance (or % recombination)?

Answer 22

Map distance (% recombination) = # of recombinants/ total offspring x 100

Question 23

m.u. is the same as ___________

Answer 23

% recombinant

Question 24

If no crossing over happens then the genotype would be the same as ________________

Answer 24

The parents

Question 25

How can you tell genes are linked when looking at a data?

Answer 25

When the two parental phenotypes are the 1st highest & second highest

Question 26

How can you which numbers in a data represents a single cross over?

Answer 26

The numbers that are 3rd & 4th highest (common ones after the two parental phenotypes)

Question 27

How can you tell which number represents a double crossover in a data?

Answer 27

The lowest number represents a double crossover

Question 28

When a single crossover occurs what happens/

Answer 28

The two genes on the end changes but not the middle gene

Question 29

In a double cross over what happens?

Answer 29

Only the middle gene changes

Question 30

If it says what is the frequency (%) of a certain parental gene what do you have to do?

Answer 30

Fidn the total frequency(%) of parental genes & divde it by to for the certain parental gene

Question 31

When you find the total % recombination what should you do?

Answer 31

Divide that number by 2 so you have the % recombination for each recombinant

Question 32

How do you find the % recombination in a double cross?

Answer 32

Multiple the two single % recombination together

Question 33

How would find the total % or amount of offsprings that will have the parental genotype (no crossover)?

Answer 33

100- all the single cross over % - double crossover %

Question 34

Interference (I) represents what?

Answer 34

The amount or % of double crossover that didnt occur

Question 35

What is the formula for interfernce?

Answer 35

I = 1- C (C- coeffiecient of coincidence which tell the % or amount of double crossover that did occur)

Question 36

What is the formula to calculate C in interfernce?

Answer 36

Observed # of double crossover/ expected # of double crossover

Question 37

Interference is used for what type of crossing over?

Answer 37

Double crossover

Question 38

When you see the words recombinant genes what does that tell you?

Answer 38

That crossing over has to occur (usually single crossover if middle gene stays the same)