Mendel s law of separation and the law of free combination?

The Mystery of Genetics: 2020 New College Entrance Examination: High School Biology - Mendel's Law of Separation (1).

1.Traits are controlled by genetic factors.

2.Genetic factors are present in pairs in somatic cells.

3.Genetic factors do not fuse, do not disappear.

4.Genetic factors are randomly assigned to individual gametes.

Traits are controlled by genetic factors, which exist in pairs in somatic cells, which exist in a single form in gametes and are randomly bound to gametes at the time of fertilization.

Mendel's pea experiment.

According to the trait segregation and the various different generations.

Statistics and then speculation.

The Mystery of Genetics: 2020 New College Entrance Examination: High School Biology - Mendel's Law of Separation (1).

How can it be okay, the law of separation is the law of separation, and the law of free combination already includes the law of separation, and this is the connection.

The essence is the separation and combination of chromosomes.

Allele segregation located on homologous chromosomes.

The Mystery of Genetics: 2020 New College Entrance Examination: High School Biology - Mendel's Law of Separation (1).

Mendel's experiment to verify the "law of segregation" hypothesis is a test experiment, and the evidence to verify the "law of segregation" hypothesis is the experimental phenomenon of the test and cross experiment, that is, the trait segregation ratio of the offspring of lateral crosses a, when the parents produce gametes, the segregation of pairs of alleles is the content of the hypothesis So a is false b, heterozygous inbreeding produces a 3:1 trait segregation ratio, which is a genetic phenomenon that needs to be explained So b is false c, when two pairs of opposite traits heterozygous produce gametes, the free combination of non-alleles is an explanation of the phenomenon of free combination Therefore, C is wrong D, and the trait segregation ratio of 1:1 between heterozygous and recessive parental crosses is the trait manifestation of the offspring of lateral crossing, so D is correct, so D should be chosen

Mendel's hypothesis of the deductive process of the sedan tung:

1. Ask the question: Mendel asked the question through the experiment of seven pairs of relative traits, why does F1 have only one ascending trait, while F2 has two traits with a ratio of 3:1?

2. Make a hypothesis: that is, Mendel's four explanations of the phenomenon of separation.

3. Deductive reasoning: If the above hypothesis is correct, then F1 crosses with recessive individuals (i.e., assay crossing), and the offspring have two phenotypes in a ratio of 1:1.

4. Verify the hypothesis: Conduct a cross-crossing experiment to observe the phenotype and proportion of offspring, and the experimental results are completely consistent with the results of inference.

5. Conclusion: Mendel's law of separation.

The essence of the law of segregation is that the two different alleles of the relative traits are independent of each other and do not contaminate each other, and when the gametes are formed, they are separated from each other and enter different gametes respectively, resulting in half of the gametes carrying one allele and the other half of the gametes carrying another allele.

According to Mendel's hypothesis, heterozygous, that is, the F1 generation CC, can form two gametes containing C and C respectively when producing gametes, with a ratio of 1:1. So just verifying this can confirm the law of separation.

The cross-crossing is to use this heterozygous to mate with the recessive homozygous, because the recessive homozygous CC will only produce one gamete C, and because it is a recessive gamete, it will show the genotype of the gamete when it combines with any gamete to form an allele, so the F1 cross-crossing shows dominance: recessive = 1:1, which proves the genotype of F1.

The law of separation was confirmed.

The decision point of this law comes from molecular biology and other aspects, which is determined by the characteristics of the genetic material, in fact, if the trait he chooses is not unlinked, he will find that the "law" is not so accurate.

The Law of Separation: Mendel's First Law.