Plants with genotype AA pollen tube defects cannot be pollinated!! Let s do the genetic problem!

Theoretically, the ratio of aa, aa, aa in the progeny is: 4 : 4 : 1 after breeding a belt, that is, aa inbred: 1aa: 2aa: 1aaaa can not pollinate, so:

The frequency of a is 4 6 = 2 3 (2 A in AA, 2 A in 2AA, 4 A in total);

The frequency of a is 2 6 = 1 3 (2 A in 2AA).

So, after another generation, aa is 2 3 2 3 = 4 9;

The aa frequency is 2 2 3 1 3 = 4 9;

The AA frequency is 1 3 1 3 = 1 9

Note: The genotype frequency is calculated as (a+a)2 = aa + 2aa + aa

aa is self-inbred, and aa:aa:aa=1:2:1aa is lethal in the F1 generation, then.

A gene frequency = 2 3 A gene frequency = 1 3

According to Hardy Weinberg's law of equilibrium AA genotype frequency = square of a gene frequency, AA genotype frequency = 2 * a gene frequency * a gene frequency AA genotype frequency = square of a gene frequency.

Then the second generation of the child aa=2 3*2 3=4 9

aa=2*2/3*1/3=4/9

aa=1/3*1/3=1/9

1.Suppose there are 120 plants on the island in the progeny of aa:aa; aa=1;2;1 So the aa produced is 30 aa has 60 aa has 30 2

In the second generation of the offspring, aa produces all AA, that is, there are 30, AA produces AA aa aa according to the proportion, each has 30 15 does not produce offspring If it is the offspring, then AA=30+30+15=75 AA=60+30=90 AA=30+15=45, so the ratio is 5:6; 3 Personal Opinion Hope to be right.

If there is more than one family member with your girlfriend, it is a pity to say that it will be inherited, if there is only one case of your girlfriend in several generations, then it is not a genetic problem, it may be caused by the nutritional imbalance when she is in her mother's womb and the environment where her mother is located. According to the situation you described, it will not be inherited, if you are very concerned about this matter, it is better for you to go to the hospital for identification, otherwise, if your girlfriend finds out about it, she will be unhappy, so it is better to talk about it. Be honest with ruu

If 30 individuals of the AA genotype and 20 individuals of the AA genotype account for the parents, the AA individuals in the parents are 50%. Then the gene frequency of parental a = (30 2 50%) 30 + 20 +50%) 2] = 55Analysis:

Genes exist in pairs in organisms, for example, an individual has two A genes. So 30 has only one A gene. The same goes for others.

If the parent's A gene frequency is 55, then the A gene frequency is 45%. The plant is self-pollinating, and the genotype frequency of AA = 30% + 50% 1 4 =. Analysis:

If 30 individuals with AA genotype in the parents are the offspring, all the genotypes of their offspring are AA (30). 50% of the parents are AA individuals, inbred (AA AA), and 1 4 of their offspring are AA, i.e. So the genotype frequency of AA in F1 is 30%+50% 1 4=.

AA accounts for 30, AA accounts for 20, AA accounts for 50, A accounts for (30 + 50 2) = 55

AA in F1 consists of two parts.

1 is the original AA-30, and 2 is the sum of the AA.

The genotype and proportion of the inbred offspring of individuals with genotype AA is: aa:aa:

AA=1:2:1, in which AA pollen is aborted and the genotype and proportion of gametes produced by females are a:

a=1:1, since aa cannot produce normal germ cells, the genotype and ratio of male gametes are a:a=2:

1, therefore, mating freely until F2, the genotype frequency of aa = 12 1

3 16,a gene frequency = 5

6, so the ratio of normal plants to pollen aborted plants in F2 plants is 5:1 Therefore, C

Summary. According to the title, the flower color of a plant is controlled by multiple pairs of independently inherited genetic factors, and each pair of genetic factors has at least one dominant genetic factor. Therefore, the genetic law of flower color of this plant can be explained by multifactorial inheritance.

According to the title, the flower color of a plant is controlled by multiple pairs of independently inherited genetic factors, and each pair of extinct wide culture transmission factors has at least one dominant genetic factor. Therefore, the genetic law of the flower color of the plant can be explained by multifactorial inheritance.

In multifactorial bereavement, each trait is controlled by multiple pairs of genes, each of which contains two alleles, one from the mother and one from the father. If each pair of slippery genes has at least one dominant allele, the trait is now a dominant phenotype, otherwise it is a recessive phenotype.

Assuming that the flower color of the plant is controlled by n pairs of genes, and each pair of genes has at least one dominant allele, the probability of the dominant phenotype of the plant flower color is: p = 1 - 1 2) n Similarly, the probability of the plant flower color showing a recessive phenotype is: 1 - p It should be noted that in multifactorial inheritance, the allele combination of each gene pair is very complex, so more specific analysis is needed to determine the genetic law of the plant flower color.

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The flower color of a plant is purely controlled by multiple pairs of independent genetic factors, and each pair of genetic factors has at least one dominant genetic factor before it blooms safflower, and the rest blooms white flowers. A plant individual in which each pair of genetic factors is heterozygous is self-bred, and the offspring are safflower: white flower 1 27:

37。Study: (1) Please analyze that the flower color of the plant is controlled by several pairs of genetic factors, and briefly explain the reasons.

2) From this we can conclude what is the connection between the law of separation and the law of free combination.

1) The flower color of the plant is controlled by 4 pairs of genetic factors. The rationale is as follows: Assuming that the flower color of the plant is controlled by n pairs of genes, and each pair of genes has at least one dominant allele, the probability that the plant will exhibit a dominant phenotype is:

p = 1 - 1 2) n and Genyan Xiang Nai According to the title of the feast, the plant only blooms safflower when each pair of genetic factors has at least one dominant genetic factor, therefore: p = 1 2) 4 = 1 16 means that the probability of the plant's rough spring flower color showing a dominant phenotype is 1 16, and according to the title, the ratio of safflower:white flowers in the offspring is 27:

37, so the flower color of the plant is controlled by 4 pairs of genetic factors.

2) Since each pair of genes in this plant has at least one dominant allele, it conforms to the law of segregation. In a self-homozygous individual, the two alleles of each gene in their offspring are derived from the two parents of the individual, and thus conform to the law of free group age width rolling. The law of segregation and the law of free combination are both fundamental laws that describe genetic variation, and they describe the laws by which genes are separated and combined in the process of posthumous transmission.

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Plants with genotype AA can produce two types of pollen, i.e., pollen containing the A gene and pollen containing the A gene; Plants with a genotype of bb can also produce two types of pollen in the wild, namely pollen containing the B gene and pollen containing the B gene After removing the cell wall, these protoplasts are fused, and if only the two are considered to be fused, 10 genotypes of fused spinal cells can be obtained, namely AA, BB, AA, BB, AA, AB, BB

Therefore, b

It should be that Mori oak tease is to get eight kinds. AA will get A and A two kinds of flowers such as trap pollen, BB will get B and B two, when the protoplast is fused, the pollen of the same genotype will be fused to get AA, AA, BB, BB four, and there are not the same genotype pollen fusion ab, ab, ab, ab

There are four kinds, so there are 8 in total.

f1: aa aa aa, aa, aa, the ratio is 1:2:1;

F2: Since AA cannot pollinate, it needs to be discussed separately.

1) Self-pollination: AA flowers cannot be pollinated and have no offspring; AA self-inbred is all AA; aa is self-inscribed with f1. You can get aa:aa:aa=3:2:1

2) Cross-pollination: It is regarded as random mating, and AA flowers cannot be pollinated but can be pollinated, so the paternal gamete type a:a=2:

1, the female gamete type a:a=1:1, so the offspring aa:

aa：aa=2:3:1.

Answer:. Analysis: From the question, it is known that the individual of the AA genotype accounts for 50%, and the gene frequency of A is 30% 1 2 50% 55%.

Gene frequency of aa in F1: 30% + 50% 1 4=. This question is the 2010 Shanghai College Entrance Examination question.

Solution process: In F1, the only ones that can produce AA are the parent's AA*AA and AA*AA

So, the calculation process is: 5 10 times 5 10 + 5 10 times 3 10 times 1 2 = 13 40

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