A narrow, deep, v-shaped depression across the continental slope is called a ____

The following F2 results occur from a dihybrid cross (AaBb x AaBb): purple: A_B_ 9/16 white: aaB_ 3/16 white: A_bb 3/16 white: a

e-lub [12.9K]

Answer:

b. 3 (whilte) : 1(purple)

Explanation:

The first dihybrid crossing is between AaBb x AaBb

Now, if the double heterozygous traits self crossed, we have the following gametes shown below for the F₂ crossing.

AaBb = (AB, Ab, aB, ab)

AB Ab aB ab

AB AABB AABb AaBB AaBb

Ab AABb AAbb AaBb Aabb

aB AaBB AaBb aaBB aaBb

ab AaBb Aabb aaBb aabb

We were being told that the results are;

purple: A_B_ 9/16

white: aaB_ 3/16

white: A_bb 3/16

white: aabb 1/16

From above, we can see that the same is true;

For Purple color; we Have (AABB and AaBb) since A is dominant to a and B is dominant to b.

∴ From the above punnet square; we have 9 purple colors which are:

(AABB, AABb, AaBB, AaBb, AABb, AaBb, AaBB, AaBb, AaBb) = 9/16

white: aaB_ ( since B is dominant to b, it can be either BB or Bb)

= (aaBB, aaBb, aaBb) = 3/16

white: A_bb ( since A is dominant to a, it can be either AA or Aa)

= (AAbb, Aabb, Aabb) = 3/16

white: aabb i.e homozygous recessive = (aabb) = 1/16

Furthermore, the question goes further by saying:

If a double heterozygote (AaBb) is crossed with a fully recessive organism (aabb), what phenotypic ratio is expected in the offspring?

If AaBb self crossed, we have: (AB, Ab, aB, ab)

If aabb self crossed, we have: (ab, ab, ab, ab)

AB Ab aB ab

ab AaBb Aabb aaBb aabb

AaBb ( purple)

= 4/16

= 1/4

= 0.25

= 25%

Aabb (white)

= 4/16

= 1/4

= 0.25

= 25%

aaBb (white)

= 4/16

= 1/4

= 0.25

= 25%

aabb (white)

= 4/16

= 1/4

= 0.25

= 25%

Now the proportion of white to purple = (25%+25%+25%): 25%

= 75%:25%

= 3(white):1(purple)

We can therefore conclude that the expected phenotypic ratio in the cross between a double heterozygote (AaBb) with a fully recessive organism (aabb) yeids;

3 (whilte) : 1(purple)

8 0

3 years ago

Imagine you do a test cross between a purple-flowered pea plant having serrated leaves (a dominant trait) and a white-flowered p

Rom4ik [11]

Answer:

genes for flower color and edge shape are linked. They do not assort independently.

Explanation:

<u>Available data:</u>

test cross between a purple-flowered pea plant having serrated leaves and a white-flowered pea plant having smooth edges.
serrated leaves → dominant trait
smooth edges → recessive trait
purple color → dominant trait
white color → recessive trait
F1: 4 purple-serrated:1 purple-smooth:1 white-serrated:4 white-smooth.

There are two genes involved in the cross. The expected ratios are 1:1:1:1 because we assume genes assort independently. However, we see a different phenotypic distribution. When phenotypic ratios differ from the expected ones, it means that genes are linked.

To know if two genes are linked in the same chromosome, we must observe the progeny distribution. If individuals, whose genes assort independently, are test crossed, they produce a progeny with equal phenotypic frequencies 1:1:1:1. 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 double heterozygote parent

5 0

2 years ago

Description of Building the Tree of Life

Leya [2.2K]

Answer:

In this way, the tree of life is a symbol of a fresh start on life, positive energy, good health and a bright future. As a symbol of immortality. A tree grows old, yet it bears seeds that contain its very essence and in this way, the tree becomes immortal. As a symbol of growth and strength.

Explanation:

The Tree of Life symbol represents our personal development, uniqueness and individual beauty. Just as the branches of a tree strengthen and grow upwards to the sky, we too grow stronger, striving for greater knowledge, wisdom and new experiences as we move through life.

7 0

2 years ago

A scientist studied four fossils of a marine mammal dating back to 50 million years, 45 million years, 40 million years, and 30

Anastasy [175]

The 30 million years ago, because its the closest one to us. Wait is there a picture to it ?

7 0

3 years ago

Read 2 more answers

Why will many species of bird migrate to warmer climate during the winter

Doss [256]

Bird migrations began with the recession of the glaciers during the ice age. You will notice a great increase in insects in the spring time and early summer.The birds moved North to take advantage of this increase in the food supply that followed the warming in the spring and early summer. Their reproductive organs temporarily developed so they could lay eggs and raise a family. Look at the early flush of Night crawlers in the moist times of the early rains. By mid summer most of the insects have matured, mated and died. Their eggs have hatched and turned to larva and moved underground until next spring. The shortening of the days causes the reproductive functions to decrease and signals the birds that the food will soon become scarce. They move back to the area that makes it the easiest to find food and avoid freezing. which of course is the warmer climates nearer the equator. Not all birds move past the Tropics at approximately 30 degrees. Some like Chickadees may move down from Mi or Mn or Canada only as far south as Indiana. Some migrations may be quite short. For example from the mountains down to the plains. They don't generally reproduce in the warmer winter climes they migrate to. In the spring time they migrate along paths of the retreating glaciers. As the climate warms away from the tropics the birds follow the emerging insects etc to the birds selected breeding grounds.with increased insects and longer days to feed the hatching's. It is necesary to understand why they move to cooler climates in the summer to under stand why they move to eh warmer ones in the fall. As the days shorten the food supply dwindles and the babies have fledged. They move to warmer climates in winter to rest and refuel for the next years migration.

8 0

3 years ago

A narrow, deep, v-shaped depression across the continental slope is called a _____ canyon. *