Discover problems-propose hypotheses-deductive reasoning-experimental verification

Self-pollination, cleistopollination, purebred in nature

Have multiple pairs of relative traits that are easily distinguishable

Short growth cycle and large number of offspring

Detasseling of pistils during flower bud stage - bagging - pollination - bagging again

Test cross experiment: cross the individual to be tested with a recessive homozygote and observe the phenotypic proportion of the offspring

Self-crossing: Make the individual to be tested self-cross and observe whether there is separation of traits in the offspring.

Pollen identification: For plants, pollen can also be taken to identify genotypes

haploid breeding

Biological traits are determined by genetic factors

Genetic factors in somatic cells exist in pairs

When an organism forms a germ cell and a gamete, pairs of genetic factors separate from each other and enter different gametes.

During fertilization, the union of male and female gametes is random

In the somatic cells of organisms, genetic factors that control the same trait exist in pairs and do not fuse.

When gametes are formed, pairs of genetic factors separate. The separated genetic factors enter different gametes and are passed on to offspring along with the gametes.

Eukaryotic organisms that reproduce sexually

intranuclear genetic factors

Pure yellow round peas × Pure green wrinkled peas → (F1) All yellow round peas

F1 self-crossing→yellow circle:green circle:yellow wrinkle:green wrinkle≈9:3:3:1

The inheritance of each pair of relative traits follows the law of segregation

The isolation and combination of genetic factors that control different traits do not interfere with each other

During the formation of gametes, pairs of genetic factors that determine the same trait are separated from each other, and genetic factors that determine different traits are freely combined.

Primary spermatocytes: the cytoplasm divides equally to form two secondary spermatocytes

Primary oocyte: the cytoplasm divides unevenly to form secondary oocytes and the first polar body

Secondary spermatocytes: the cytoplasm divides equally to form two sperm cells, which are transformed into sperm.

Secondary oocyte: the cytoplasm divides unevenly to form the egg cell and second polar body

First polar body: the cytoplasm divides equally to form two polar bodies