Please answer all questions Define 1 Wild type 2 Epistasis

Please answer all questions

Define

1. Wild type –

2. Epistasis –

Fill in the Blank

3. Two genes may interact effecting one trait and resulting in novel phenotypes with an F2 phenotypic ________________ ratio.

4. Under ________________ conditions, conditionally lethal mutants will die.

True or False

5. Penetrance is the degree or intensity with which a particular genotype is expressed in a phenotype.

6. Continuous traits are usually controlled by multiple genes and may be influenced by the environment.

Short Answer

7. Describe the inheritance pattern(s) of blood types.

8. When studying a newly discovered flowering plant in Costa Rica, you collect data on its petal color in an effort to determine how this trait may be inherited. You find that 852 flowers are red, 331 are white and 389 are yellow. What are the possible inheritance patterns, and how could you definitely conclude which of these possibilities is the true mode of inheritance?

Solution

Wild type- wild type phenotype refers to characteristics that occurs naturally in a breeding population.

Epistasis - it refers to a phenomena when one gene’s expression is dependent on the presence of another gene(s), called the modifier gene.

9:16

Let\'s take an example of comb varieties in chicken

We have two pure breeds : wyandotte whose phenotype is a rose comb and brahmas having the phenotype of a pea comb, when crossed with each other, they create a completely new phenotype of a walnut comb. Let\'s look at the ratio:

Parental cross: rose comb x pea comb

F1                   : all walnut combs

F2                   : 9 walnut : 3 rose: 3peas : 1 single

Hence the ratio is 9:16

Under the restrictive or nonpermissive condition conditions, conditionally lethal mutants will die.

Conditionally lethal mutants are those which have an allele that will make the survival of the species difficult only in a specific condition.

True. for example if a mutation in a gene gives the species a particular characterisitc which has 97%penetrance, only 97% of those with the mutation will develop that characteristic and 3 % will not.

True. multiple genes affect continuous traits. For such complex gene interactions, the traits are influenced by environmental factors too. For example, height and skin color.

There are four basic blood types which are A, B, AB and O and together with the Rh factor, these can be +ve or -ve.
A and B are dominant, while O is recessive.

Blood type

A

B

O

A

A

AB

A

B

AB

B

B

O

A

B

O

For Rh factor, Rh (+)ve is dominant.

So if the any one or both parents have Rh (+)ve factor, the progeny will be Rh(+)ve.

If both parents are Rh(-)ve, the progeny will be Rh (-)ve

Father

Mother

D

D

d

Dd

Dd

d

Dd

Dd

100% Rh (+)ve children

Father

Mother

D

d

d

Dd

dd

d

Dd

dd

50% Rh(+)ve children

Red: 852
White: 331
Yellow:389

According to the given data, red is dominant and white is recessive and yellow is a result of incomplete dominance of both white and red phenotype.

It can\'t be codominance, because codominance involves both phenotypes being expressed in different parts of the organism: you would end up with red and white spotted flowers.

It isn\'t complete dominance, because the red x white cross produces yellow flowers.

the yellow phenotype is the result of the heterozygous red/white genotype. the yellow flowers are produced as a result of incomplete dominance between the Red and white alleles.

If we assign the red phenotype letter R and the white phenotype the letter w, yellow will be Rw.

The inheritance pattern will be as follows.

Red(R)

White(w)

Yellow(Rw)

Red(R)

RR(red)

Rw(yellow)

RR(red), Rw(yellow)

White(w)

Rw(yellow)

ww(white)

Rw(yellow), ww(white)

Yellow(Rw)

RR(red), Rw(yellow)

Rw, ww

RR(red), Rw(yellow), ww(white)

Blood type	A	B	O
A	A	AB	A
B	AB	B	B
O	A	B	O