1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
AleksAgata [21]
2 years ago
10

You are doing a genetics experiment with the fruit fly. In the "P" generation, you cross two true-breeding flies. The female par

ent is brown and wingless and the male parent is black with normal wings. All of the flies in the F1 generation are brown and have normal wings.
Indicate the alleles associated with dominant phenotypes by uppercase letters and alleles associated with recessive phenotypes by lowercase letters. Assume the genes are not found on a sex chromosome. Indicate the color alleles as "B" and "b" the wing alleles by the letters "N" and "n
(a) What are the genotypes in P generation?
(b) What are the genotypes in F1 generation?
(c) You now take an F1 female and cross her to a true-breeding black, wingless male. and you count 1600 offspring in the F2 generation and you get:
85 brown winged flies
728 black winged flies
712 brown wingless flies
75 black wingless flies
These results suggest the genes are on the same chromosome, why?
(d) What is the genetic distance between the color and wing genes?
(e) A series of fruit fly matings shows that the recombination frequency between the gene for wing size and the a third gene (the gene for antenna length is 5%. List all possible recombination frequencies between the gene for color and the gene for antenna length and draw the possible chromosome map(s).
Biology
1 answer:
r-ruslan [8.4K]2 years ago
4 0

Answer and Explanation:

<u>Available data: </u>

  • Allele "B" expresses brown, and "b" expresses black the wing
  • Allele "N" expresses normal wings, and allele "n" expresses wingless.
  • "P" generation: cross two true-breeding flies: brown and wingless with black with normal wings.
  • All of the flies in the F1 generation are brown and have normal wings.

(a) <em>What are the genotypes in P generation?</em> BBnn  x  bbNN

BBnn= brown and wingless

bbNN=black and normal wings

(b) <em>What are the genotypes in F1 generation? </em>The F1 genotype is 100% Heterozygote, BbNn

(c) <em>You now take an F1 female and cross her to a true-breeding black, wingless male</em>: BbNn   x   bbnn

and you count:

  • Total number of individuals, N= 1600
  • 85 brown winged flies, B-N-
  • 728 black winged flies, bbN-
  • 712 brown wingless flies, B-nn
  • 75 black wingless flies, bbnn

<em>These results suggest the genes are on the same chromosome, why? </em>

To know if two genes are linked in the same chromosome, we must observe the progeny distribution. If individuals, whos genes assort independently, are test crossed, they produce a progeny with equal phenotypic frequencies 1:1:1:1, in the example this would be 1/4 BbNn, 1/4 Bbnn, 1/4 bbNn, 1/4 bbnn, or 400 individuals per genotype.  

But if instead of this distribution, we observe a different one, that is that phenotypes appear in different proportions, we can assume that genes are linked in the same chromosome of the double heterozygote parent. In the present example, the proportion of the F2 has a different distribution, so that is how we know they are on the same chromosome, very close to each other. The F2 is distributed like this: 85 B-N-, 728 bbN-, 712 B-nn, 75 bbnn.

(d) <em>What is the genetic distance between the color and wing genes? </em>

We need to know that 1% of recombination frequency = 1 map unit = 1cm. And that the maximum recombination frequency is always 50%.

The map unit is the distance between a pair of genes for which every 100 meiotic products one of them results in a recombinant one.

In the present example, the genotype, in linked gene format, of the double heterozygote parent is Bn/bN.

In this way, we might verify which are the recombinant gametes produced by the di-hybrid, and we will be able to recognize them by looking at the phenotypes with lower frequencies in the progeny: 85 B-N- and 75 bbnn.

To calculate the recombination frequency we will make use of the next formula: P = Recombinant number / Total of individuals.

P = Recombinant number / Total of individuals.

P= 85 + 75 / 85 + 75 + 728 + 712

P=  160/ 1600

P= 0.1

The genetic distance will result from multiplying that frequency by 100 and expressing it in map units (MU).

Genetic distance= 0.1 x 100 = 10 MU.

(e) <em>A series of fruit fly matings shows that the recombination frequency between the gene for wing size and the a third gene (the gene for antenna length is 5%. List all possible recombination frequencies between the gene for color and the gene for antenna length and draw the possible chromosome map(s).</em>

There are two possibilities:

  • Antena--------wing------------color

                    5 MU           10 MU

<em>Where the genetic distance between the gene for color and the gene for antenna length is </em><em>15MU</em>

<em />

  • Color----------Antena---------Wing

                   5 MU                5 MU

<em>Where the genetic distance</em> <em>between the gene for color and the gene for antenna length is </em><em>5MU</em>

You might be interested in
Fiber that is ________ can bind to bile and cholesterol and pull it out of circulation. this can help to decrease blood choleste
user100 [1]
Fibre is a carbohydrate that the body can not digest or assimilate
There are two types of fibre: soluble fibre and insoluble fibre with complementary health benefits.
<span>Fibre that soluble can bind to bile and cholesterol and pull it out of circulation. this can help to decrease blood cholesterol.</span>
3 0
3 years ago
Read 2 more answers
The nematode Caenorhabditis elegans has allowed scientists to develop "fate maps" tracing cell lines back to cell origins. The t
Natali [406]

Answer:

The correct answer is E) eutely

Explanation:

Nematodes are organisms with bilateral symmetry, although their organs are coiled, sometimes one of the limbs is lost and many of sedentary life tend to radial symmetry. One of the most striking characteristics of these animals is that their growth is not produced by an increase in the number of cells that compose them, but by an increase in the size of the already existing cells; in fact, in most adult tissues the number of cells is constant, a phenomenon known as eutelia.

Eutelia is the condition of an organism composed of a constant number of cells or syncytial nuclei in all adult individuals of a species, such as nematodes, it means that body growth is not carried out by increasing the number of cells but by the growth of existing cells.

8 0
3 years ago
Read 2 more answers
The theory of evolution does not describe how
DENIUS [597]
Your answer is a: how DNA is formed.
6 0
3 years ago
Read 2 more answers
250 employees we lost 12%
Assoli18 [71]

The answer is that you only have 30 employees. What a shame.

6 0
3 years ago
Read 2 more answers
Fetures of unwarped mountains
Mariana [72]
They have almost no height or determination of a real mountain they a pretty much just a lump of dirt...
3 0
3 years ago
Other questions:
  • When the kidneys detect an increase in salt they respond by
    9·2 answers
  • Which type of neuron carries impulses from sense organs to the spinal cord or brain?
    7·1 answer
  • If there is a loss of balance in biodiversity, describe at least 5 possible consequences for the sustainability of life on earth
    6·1 answer
  • Give an example of a non-testable question:
    6·1 answer
  • A college student goes to the er with symptoms of headache and high fever for the past two days. a lumbar puncture is performed
    11·1 answer
  • Which of the following is the best way to slow the greenhouse effect? drive more often stop using electricity use energy sources
    8·2 answers
  • Write any two uses of Rocks and Minerals of each?​
    14·2 answers
  • I will give brainliest for the first person who guess this correctly.
    14·2 answers
  • What are the building blocks of all organisms?
    11·1 answer
  • Is this statement true or false? a peninsula is a body of land that is surrounded by water on two sides
    14·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!