Will acquired changes affect gene inheritance?

The reason why humans have been able to reproduce for thousands of years is that genes have been passed down. Then some people have asked, will acquired changes affect the inheritance of genes? Here, acquired changes mainly refer to the acquired living environment, personality formation, physical changes, myopia, disability, etc.

The answer is yes. Why do you say that? Let’s talk about it today.

01. Postnatal changes will affect the inheritance of genes

The reason why acquired changes affect the inheritance of genes is because the genome has changed (this is actually not something we need to worry about, because we generally cannot control it).

I believe everyone who has studied biology knows this: why are brothers and sisters different?

The human genome has 3 billion bases and 46 chromosomes. These bases are mutating at a certain rate, and the chromosomes are constantly reorganizing (linked exchange). All of these determine that you and your relatives are different (of course, some areas are the same, otherwise paternity testing would not be possible).

Many people may say, isn't this nonsense? But it must be said that sometimes, some external factors will stimulate changes in the body's pathways, thereby changing genes (such as the famous susceptibility to AIDS). Of course, the external environment will also have a shaping effect, otherwise why are there so many racial differences in the world.

02. Will personal behavior affect genes?

Some people may ask, ignoring the changes in the genome due to genetic recombination, will personal behavior affect heredity? The answer is yes.

The famous epigenetics is about this. This subject was born late, so it does not appear in many high school textbooks. The theory of this subject is that the DNA sequence does not change, but the gene expression undergoes heritable changes, such as the differences between typical identical twins.

Common epigenetic inheritance is mainly DNA methylation, which silences or activates the expression of some genes through methylation changes.

For example, smoking can directly affect epigenetic changes in sperm and pass them on to the next generation. (1)

For example, obesity can cause epigenetic changes in sperm that are passed on to the next generation (2)

If you want to know specifically whether a certain disease is hereditary, please google scholar (Google Scholar, not Google web search)

Enter the name of the disease you are interested in + methyation to see if anyone has published relevant research (because methylation is the easiest to do in epigenetics and is also the most widely studied)

03. Inheritance of some diseases

A typical example is a viral disease. Actually, it is not appropriate to call it genetic here, but some diseases can infect babies.

For example, AIDS

As for the others, there is still a lack of research, so I won't list them one by one. As for the disability mentioned by some friends, it is not hereditary. In fact, there is no need to worry.

But myopia is hereditary

In the article Teikari JM, O'Donnell J, Kaprio J, et al. Impact of heredity in myopia[J]. Human heredity, 1991, 41(3): 151-156.

Heritability of myopia was 0.58 (0.74 for males and 0.61 for females).

That is, the heritability of myopia is as high as 0.58. It is strongly recommended to pay attention to diet and environment when preparing for conception. This is by no means alarmist.

04. Supplement: Genetic predisposition/susceptibility to disease

Regarding the genetic tendency/susceptibility to disease, I mentioned it in an article before. If you are interested, you can go and have a look. The path is attached: "The "inheritance" of common diseases such as cancer and cardiovascular disease - Li Lei's article - Zhihu

https://zhuanlan.zhihu.com/p/20650381》

The disease inheritance issue that I want to talk about today, in fact, it is not quite appropriate to use the word "inherited".

Because this is not similar to our traditional inheritance of "dragons give birth to dragons and phoenixes give birth to phoenixes". It is not a special genetic disease, but the "inheritance" of common diseases.

This inheritance is a kind of tendency inheritance, or it can be said to be a kind of risk factor inheritance.

This is what we discovered when processing various data. Many diseases, especially chronic diseases such as cancer, cardiovascular disease, diabetes, etc., have very significant familial clustering problems. The manifestation is that in a family, almost all direct descendants have a higher probability of suffering from the disease than the normal population.

In general, these diseases include but are not limited to the following

Chronic diseases: cancer; coronary heart disease, diabetes, osteoporosis

Physical signs: blood pressure, cholesterol

The reasons here are complex, including external factors and genetic factors

External causes mainly include living habits and living environment. For example, if a family likes to eat salty food, then the proportion of hypertension in this family will definitely be high.

The internal cause is genetic factors, that is, gene problems. Many diseases are complex diseases, determined by multiple genes, and each gene is very large (basically the smaller ones are several thousand bases, and the larger ones are hundreds of thousands of bases). Many families will have some mutations, and this mutation may not directly cause the disease, but it will increase the risk, or susceptibility.

Therefore, in the hospital, responsible doctors will definitely ask about your family medical history.

At the same time, please pay attention to your family to see if there is a similar phenomenon. If so, you must pay more attention to it. Regular physical examinations, focusing on certain items (for example, families with high blood pressure must pay attention to blood pressure values)

At the same time, you should pay attention to certain symptoms. Most indicators are statistical data, such as the normal range of high blood pressure is 90-140. This range is very large. You cannot think that 90 before and 139 now are both normal. In fact, for you, this is already very abnormal because your blood pressure has increased by 55%. Therefore, you must read the physical examination form yourself and compare it with the data of previous years.