Questions about the phenomenon of variation and heredity

The heredity of living things is relative, whereas the variation of living things is absolute.

Heredity, variation.

It's so simple, isn't it?

Abstract Non-hereditary variation: Variation caused by the influence of the external environment, the genetic material has not changed, and cannot be passed on to offspring. For example, cats and dogs have acquired tail docking, and their offspring are just as healthy and have tails.

Non-hereditary variation: Variation caused by the influence of the external environment, the genetic material has not changed, and cannot be passed on to future generations. For example, cats and dogs have acquired tail docking, and their offspring are just as healthy and have tails.

Examples of genetic phenomena:

In general, the nose is large and high and the nostrils are wide. If one of the parents has a straight nose, it is very likely that it will be passed on to the child.

Generally, if one of the parents has dimples, the remaining children generally have dimples.

Red-green color blindness, caused by an X-linked recessive gene, occurs in about 10% of males and less common in females. In men, the gene that causes color blindness comes from the mother, who is a person with color blindness or a carrier of the gene with normal vision. The color blindness gene does not come from the father because the father provides the Y chromosome.

Daughters of colorblind fathers are rarely colorblind, but are often carriers of the colorblind gene.

Isodominant inheritance, both genes are expressed. For example, sickle cell anemia; If a person has a normal gene and an abnormal gene at the same time, it is possible to produce both normal and abnormal hemoglobin.

V-shaped hairline, generally speaking, if one parent has a V-shaped hairline, their child will also have a V-shaped hairline.

Examples of Variation:

Down syndrome, also known as congenital stupidity or Down syndrome, is a condition caused by a chromosomal abnormality (an extra chromosome 21). 60% of the children were aborted in the early stage of the fetus, and the survivors had obvious mental retardation, special facial features, growth and development disorders, and multiple malformations.

If you take vegetables to outer space, they will have obvious mutations when they return to Earth, and if they are larger, they will be larger.

The same wheat seeds are sown in different environments under different water and fertilizer conditions, and the fullness of the seeds is different.

The colors of roses are red, white, etc.

Dwarf rice plants appear in tall rice fields.

Heritable variation: different flower colors of goldfish and tulips, non-heritable variation: acquired myopia.

Seedless watermelon is caused by chromosomal variation, if the branches of seedless watermelon are taken for vegetative propagation, the result is still seedless watermelon, which is heritable variation; Seedless tomatoes are caused by the application of auxin, and if the branches of seedless tomatoes are taken for vegetative propagation, the fruits obtained without touching auxin still have seeds, and the childless trait is not inherited.