Pea gray seed coat A is dominant against white seed coat a , and yellow cotyledons B is dominant

AAB crosses with AABB to produce F1AABB, which is divided into two segregation laws, that is, AA and BB, and AA is inbred to produce the color separation ratio of the seed coat is 1+2:1That's 3:

1.Since the color of the cotyledon can only be expressed in the F3 generation. So the F2 generation separation ratio is also 3:

1.Then aa aa is homozygous, and the inbred offspring do not undergo trait separation. The self-inbreeding of 1 2 BB produces 1 8 BB, 1 4 BB, 1 8 BB, so the addition law should be applied.

The shape separation ratio is 1 4 + 1 8 + 1 4 +: 1 8 + 1 4, that is, 5:3

Got it, I'm also a freshman in high school.

First of all, there is no interaction between the two genes, A and B, and the segregation ratio of the same seed is segregated, so the segregation ratio of the two traits should be the same. Secondly, what is sought is the separation ratio of seed coat color and cotyledon color of the seeds produced by F2 plants, the seeds of F2 are F3, not F2, you can first find the ratio of the genotype of F3, and then get the separation ratio, I calculated that it is 5:3.

You'd better ask the teacher, and if there's something wrong with the analysis, please let me know.

The seed coat is a part of the plant, and the genotype is the same as the genotype of the plant, so it is 3:1;

And the cotyledons are not actually part of the plant. Cotyledons are the "juvenile state" of the next generation of individuals, and its genotype is not related to the mother's parent. It's like an unborn fetus whose genotype is not related to the genotype of the pregnant woman.

So the genotype of the second generation of cotyledons is actually the same as that of the third generation of plants.

Although the color of the pea seed coat is genetically controlled, the seed coat is developed from the ovary wall of the female parent, so the color of the seed coat is the same as that of the female parent. Therefore, the seed coat of F1 (heterozygous) seeds is all gray. That is to say, the genotype of the seed coat conforms to the law of gene segregation, but the phenotype satisfies the law of segregation one generation later than the genotype.

So the genotype of the seeds produced on the F2 plant is gg:gg:gg=3:

2:3, so the cotyledon genetic composition of the seeds on the F2 plant is homozygous probability 3 4

This, the genotype of F1 cotyledons is gg, gg, gg. The ratio is 1:2:

1。i.e. the probability of homozygous is 1 2. They are still homozygous in the next generation, so they are still 1 2

Among the offspring of the heterozygous gg, 1 2 is homozygous, so it is 1 4So a sum is 1 2 + 1 4 = 3 4

The seed coat of the seed is the genotype of the plant itself; The genotype of cotyledons is the genotype of the seed, that is, the genotype of the cotyledons is the same as the plant that the seed grows into. For example, in F1 plants, the seed coat of the seed is the same as the F1 genotype, and the cotyledons are the F2 genotype.

Explanation: The seed coat is all gg, so gray.

The cotyledons of the seeds, the genotype is the genotype of F2, so there are three kinds: gg, gg, and the seed coat of gg, gg:gg:gg=1:2:1

The cotyledons of the seeds, i.e., the genotype of F3. In F2, 1 2 is homozygous individuals (gg, gg), and their F3 is homozygous, where 1 2 is heterozygous, and in their F3, 1 2 is homozygous, so 1 2gg 1 2 = 1 4 is homozygous, so d: 1 2 + 1 4 = 3 4

(1) According to the proportion of hybrid offspring, it can be judged that the genotypes of the parents are YYRR and YYRR (2) In the hybrid progeny F1, there are 6 genotypes and 4 phenotypes, which are yellow round grains (1yyrr, 2yyrr), yellow round grains (1yyrr, 1yyrr), green round grains (1yyrr, 2yyrr) and green wrinkles (1yyrr). The quantity ratio is 3:1:3:

1 (3) There are yyrr and yyrr in the homozygous F1, which account for 28 14 of the total

So the answer is: 1) yyrr yyrr

The ratio of two heterozygous offspring is 1:2:1, of which the proportion of green homozygotes is 1/4 of the four Wubu, so theoretically the number of offspring in the green cavity is 1/4 of 120, and the answer is b

Yellow yyrr, green yyrr

The ratio of yellow wrinkles to green wrinkles is 1:1, and the ratio of homozygous in F1 is 1 4 The gene composition is yyrr and yyrr, and the species are yellow round grains, green round grains, yellow wrinkles and green wrinkles; The ratio is 2:2:

1:1 The two round grains are crossed and wrinkled grains appear, indicating that both round grains are (rr), yellow and green hybrid offspring, yellow-green 1:1, indicating that the yellow parents are yy, from which the first parental gene type: yellow round grain yyrr, green round grain yyrr Crossing these two genes to draw a tree diagram can lead to the second question: The yellow round grain 1 3yyrr and 2 3yyrr in the offspring generation can be crossed with the green wrinkle grain yyrr, and the third question can be obtained.

If you don't understand something, you can continue to ask.

This question is a bit off.

The green pods of peas and the wrinkled seeds are the female parent, and the yellow pods and the seeds are round-grained paternal", the implicit condition of this sentence is: all seeds on the female parent are wrinkled grains, and all seeds on the paternal parent are round grains. Since peas are pollinated by closed flowers, it can be inferred that both the female parent and the male parent are homozygous per mu of fiber.

So the offspring are all dominant traits – round grains. This one is more pitiful.

There is one more place: note that the color of the title is a pod, not a seed coat! The color of the pod is always the same as that of the mother, and the offspring's appearance can only be seen by grinding the pea seed. So regardless of genotype, all pods of the fruit must be green in color.

Cotyledons F1 generation color separation, this is simple, not to mention.

Let's explain the color separation of the seed coat. The seed coat is developed from the beads of the ovule.

The ovule is equivalent to the mother's placenta, which is a part of the mother's body, and the genotype is the same as that of the mother. Therefore, the seed coat of the F1 generation is actually a part of the mother's body, which is equivalent to falling off directly from the mother's body. Therefore, its expressiveness is still the same as that of the parent body, and there is no color separation.

However, at this time, there are three genotypes of the F1 generation regarding the seed coat: 1AA, 2AA, and 1AA.

In the same way, the F1 generation is inbred and produces the F2 generation. The seed coat of the F2 generation is part of the F1 generation. Its genotype is the same as that of the F1 generation, that is, the three mentioned above, and their corresponding phenotypes are segregated, with a ratio of 3:1.

F2 is still with the mother, but F2 is not one plant, but many plants, some AA and AA are dominant, and some AA are recessive.

<>2) white; The sharp spike is resistant to the fierce color of the gray family.

3) Zi Yinchun generation.

The seed coat of the seeds on the F1 generation depends on the mother parent, and the genotype of the F1 generation plant is GG, so the genotype of the seed coat of the seeds on the F1 generation is GG, and it is all gray seed coat, which is correct

The color of the cotyledons of the seeds on the F1 generation depends on the parental parent, because the F1 generation is heterozygous (YY) after inbreeding, the genotype and phenotype ratio is:

yy×yyyy yy yy

Yellow, yellow, green.

Therefore, the cotyledons:green cotyledons of the seeds produced in the F1 generation are close to 3:1, which is correct

The seeds on the F1 generation have three genotypes that determine the seed coat (GG, GG, GG), and there are also three genotypes that determine the color of the cotyledons (yy, yy, yy), so the embryo has 3 3 = 9 genotypes, correct

Since the seed coat of the seeds set in the F2 generation is determined by the genotype of the mother plant, and the genotype and ratio of the determining skin in the F2 generation is 1gg:2gg:1gg, the phenotypic ratio of the seed coat of the seeds on the F2 generation is :

Gray seed coat: white seed coat is close to 3:1, correct

Therefore, choose D