Question 32 ______________ is the masking of one gene\'s phenotype by another. D

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Question 32

______________ is the masking of one gene's phenotype by another.

Dominant lethal allele

Variable expressitivity

Incomplete dominance

Epistatis

Recessive lethal allele

1 points

Question 33

In one particular breed of rabbits, their eyes can be either red, blue or black.

When a pure-breeding rabbit with blue eyes mates with a pure-breeding rabbit with black eyes the result is that all the offspring (i.e. the F1 generation) have red eyes.

When these F1 generation rabbits are allowed to mate with one another, we see a F2 generation where there are 9 rabbits with red eyes, 3 rabbits with blue eyes, and 4 with black eyes.

The genotype that produces black eyes is bb. We observe red or blue colour eyes when one B allele is present. The alleles at the hypostatic locus are R (red) and r (blue).

What is the genotype of the rabbit with black eyes from the parental generation?

rrBB

rrbb

RrBb

Rrbb

RRbb

1 points

Question 34

A group of scientists are studying antlers in caribou. They determined that a gene located on an autosome controls antler production in males and that female caribou never produce antlers. This is an example of a(n) ___________ trait.

sex-linked

sex-limited

sex-influenced

autosomal recessive

autosomal dominant

1 points

Question 35

Leber hereditary optic neuropathy (LHON) is a human disease that exhibits cytoplasmic inheritance. It is characterized by rapid loss of vision in both eyes, resulting from the death of cells in the optic nerve. A teenager loses vision in both eyes and is later diagnosed with LHON. How did this individual most likely inherit the mutant DNA responsible for this condition?

A nuclear gene from the father.

A nuclear gene from the mother.

A mitochondrial gene from the father.

A mitochondrial gene from the mother.

Any of the above answers are possible.

1 points

Question 36

In genetic maternal effect,

the mother's behaviour influences the phenotype of the offspring.

the phenotype of the offspring is determined by the phenotype of their mother.

the genotype of the offspring is determined by the phenotype of the mother.

the phenotype of the offspring is not determined by the offspring's own genotype,

the phenotype of the offspring is determined by its own genotype.

1 points

Question 37

The Himalayan allele in rabbits produces dark fur at the extremities of the body on the nose, ears, and feet. The dark pigment develops, however, only when a rabbit is reared at a temperature of 25°C or lower; if a Himalayan rabbit is reared at 30°C, no dark patches develop. What does this exemplify?

Dominance

Discontinuous trait

Continuous Trait

Polygenic Trait

Temperature-sensitive allele

Dominant lethal allele

Variable expressitivity

Incomplete dominance

Epistatis

Recessive lethal allele

Explanation / Answer

1) Epistasis

2) rrBB (black) x RRbb (blue)

RrBb (Red eyes)

RrBb x RrBb

      RB      Rb    rB    rb

RB    RRBB   RRBb RrBB RrBb

Rb     RRBb    RRbb RrBb Rrbb

rB     RrBB   RrBb   rrBB   rrBb

rb     RrBb    Rrbb    rrBb    rrbb

bb produces black

R and r are hypostatic

when one of the allele is B red or blue is observed., as all F2 generation in the parental cross were red R_B_ produces red which give 9 in the second cross. So any where in the self cross there is Rand B together they will complement each other as this is gene complementation's example, i can tell this from the ratio 9:3:4. when rr is present B is present this will produce blue, in the above punett square there are 3 such genotypes, . and when bb is present it is black in the above punett square there are 4 such genotypes.

this makes RRbb the genotype of black eyes and rrBB the genotype of Blue eyes and together RandB complement each other to produce red eyes.

34. sex influenced trait.

35. A mitochondrial gene from the mother.

36. in maternal effect, the offspring's phenotype is influenced by the mother's genotype. mRNAs from the mother's nucleus influence the offspring's phenotype. there fore the following option is applicable: the phenotype of the offspring is not determined by the offspring's own genotype,

37. Temperature-sensitive allele

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