Gene mutation mind map

Regarding the gene mutation mind map, in the DNA molecule, the substitution, addition or deletion of base pairs causes changes in the gene base sequence.

Edited at 2023-11-26 10:31:41

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Gene mutation mind map

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Outline

Gene mutations (at the molecular level) are not visible under a light microscope.

concept

In the DNA molecule, the substitution of base pairs, addition or deletion, causes changes in the gene base sequence.

Time of occurrence

It can occur at any stage of life, but mainly occurs during DNA replication. Before cell division, there are mitosis and meiosis.

individual occurrence

All organisms: eukaryotic and prokaryotic viruses. (Somatic cell mutation, germ cell mutation)

type

Spontaneous mutations (low frequency, mutations caused by errors in DNA replication, endogenous factors) Induced mutations (physical factors (ultraviolet, X-rays and other radiation), chemical factors (nitrites, base analogs) Biological factors (genetic material of certain viruses) .)

result

Generate new genes and alleles in eukaryotes.

Features

Universality, randomness (occurs on different DNA molecules in cells and different parts of the same DNA molecule at any stage of biological ontogeny), low frequency, non-directionality (production of more than one allele), heritability (If it occurs in gametes, it can be passed on to future generations according to genetic rules. If it occurs in somatic cells, it generally cannot be passed on to future generations. However, some plants can pass on to future generations through asexual reproduction).

significance

Produce new genes, the fundamental source of biological variation, provide abundant raw materials for biological evolution, and produce new traits

application

mutation breeding

It is produced during induced mutations, which increases the mutation rate and creates the required new biological varieties.

Time: In the germination state, when mitosis is vigorous, replication is prone to change.

Advantages: Increase the mutation rate and obtain more excellent types in a shorter period of time.

Disadvantages: There are often few beneficial variations and a large amount of material needs to be processed and selected. Affected by low frequency, non-directionality and randomness.

Textbook examples

Sickle cell anemia.

Direct cause: Abnormal hemoglobin. Root cause: Substitution of bases in the gene encoding hemoglobin. The base sequence is replaced.

Changes in the shape of red blood cells can be observed under a light microscope. The shape of red blood cells can be observed using a microscope to determine whether they are round or sickle-shaped.

cancer

normal cells

Proto-oncogenes express proteins that allow cells to grow and multiply normally. Tumor suppressor genes express proteins that can inhibit cell growth and proliferation or promote cell apoptosis.

internal cause

Mutation or overexpression of proto-oncogenes leads to enhanced activity of the corresponding protein. Mutations in tumor suppressor genes lead to weakening or inactivation of the corresponding protein activity.

external factors

Carcinogens that induce mutations: physical factors, chemical factors, biological factors, increase mutation frequency.

Cancer cell characteristics

Infinite proliferation, reduction of glycoproteins on the cell membrane, diffusion and transfer, loss of contact inhibition, and significant changes in morphological structure.

Proto-oncogenes and tumor suppressor genes are both a type of gene, not the same gene

There are also proto-oncogenes and tumor suppressor genes on the DNA in normal cells.

It is not the mutation of one gene that will cause cell cancer. It takes multiple gene mutations to cause cell cancer.

Proto-oncogenes and tumor suppressor genes jointly regulate cell growth and reproduction.

Cancer is not a genetic disease, but is related to genetic genes and environmental factors.

Notice

Gene mutations may occur, but the probability of low-frequency effects is very small.