Color blindness is not passed on to women, true or false?

When it comes to color blindness, everyone must be unfamiliar. Since the primary medical examination, we have been in contact with that colorful test card.

Ishihara color blind test card: identifying color blindness by using fake same color diagrams, is one of the most common color blind test methods

Picture source: reference [1]

Is the online transmission "color blindness and men do not pass on women", is it true or false? Let's take a look together!

Does the color blindness pass the men?

According to statistics from the British National Medical System (NHS), the incidence of red and green blindness in the crowd is different from the gender, with great differences. The incidence of men is 8.3%, while only 0.05%among women.

According to the different survey areas and the survey time, the proportion of data has fluctuated, but we can be sure that both men and women may suffer from color blindness, and the probability of color blindness in men is much higher than women.

Ishihara color blind test statistics in different areas of Chinese color blindness in different areas of Chinese color blindness

Picture source: reference [2]

Therefore, color blindness is only more male patients, not for men and women.

How does color blindness pass?

At first, the research magic weapon of scientists was genetic spectrum. Through the genetic spectrum chart, we can understand the incidence of genetic diseases in a family system.

The genetic spectrum of hemophilia

Picture source: reference [3]

At the same time, the comprehensive analysis of the genetic genealogy of different family departments of the same disease can be obtained whether the disease is inherited.

With the deepening of research, scientists have found that color blindness has gender and genetic characteristics. For example, in a family, if the mother is color blindness, her son must be color blindness; in a family, if her daughter is color blindness, her father must be color blindness; otherwise, it may not be established.

However, the inquiry that only analyzes the disease phenotype does not allow us to truly understand the mechanism of the disease. Entering the 20th century, the exploration of diseases entered a more micro level. Scientists have found that it is actually related to genes that decide whether to be congenital color blindness.

Micro structure of genes

Picture source: bing

Genes refer to the nucleotide fragments with genetic effects (except for the genes of certain viruses consisting of RNA, the genes of most organisms are composed of DNA), and the growth, development, and survival of each organism depends on the normal expression of genes.

Due to the regulation of genes participating in the normal physiological activities of human beings, the number of nucleotides occupied by genes is also very large. In order to alleviate cell metabolism and survival pressure, such DNA fragments are compressed, spiral, and entangled. The stick -like -we call it "chromosome".

Gene, DNA and chromosome relationship map

Picture source: reference [5]

Each of us has 22 pairs of autosomes and 1 pair of sex chromosomes. Under normal circumstances, women's sex chromosomes are XX, and men's sex chromosomes are XY.

46 chromosomes of normal men, including 44 constant chromosomes, an X chromosome and a Y chromosome

Picture source: reference [6]

Studies have found that it is determined whether we can observe the gene (OPN1LW gene) on the X chromosomes normally. A mutation direction of this gene is manifested as red and green blindness.

The OPN1LW gene that can cause traffic blindly is located on the X chromosome

Picture source: NCBI

Why are there many male patients?

For men with sex chromosome characteristics as XY, as long as the genes on the x chromosomes on the genes of color sensation (such as the lack of OPN1LW gene), it will suffer from color blindness, that is, it is impossible to correctly identify red, green and blue.

For women, only two X chromosomes determine the genetically differentiated genes at the same time, and they will be diagnosed as color -blind patients. When there is only one X dyeing gene mutation, women can mobilize another X chromosome as a compensation mechanism in color recognition to produce normal color sense. These people are called "carriers" of mutation genes.

According to the disease and genetic characteristics of color blindness, scientists will cause this chromosomal disease that causes color blindness to belong to the hidden genetic inheritance of the X chromosome. In other words, in congenital color blindness, red and green blindness is accompanied.

We can specifically observe the transmission of color blindness genes through the following pictures and forms.

The process of the sex chromosomes where the genes are delivered to the sub -dynasty

Picture source: reference [6]

Color blind genetic analysis table

Photo source: authors self -made

However, the digital ratio of the above table can only be used as the theoretical reference, and there will be a difference in order in reality. Female -blind patients have a very low proportion of the crowd, and mutant genes are concentrated on male color blind patients and female color blind carriers.

Multiplying the frequency coefficient of the mutant gene in a specific population (take Q = 8%), the specific number also confirms our conclusion: the color blindness passes the male and the male color, and the male color is more blind.

Color blind genetic feature analysis table

Photo source: authors self -made

Is color blindness only related to genes?

The occurrence of some color blindness is completely unrelated to the gene and does not have the corresponding genetic ability. This color blindness is called acquired color blindness. The acquired color blindness is often related to chronic diseases (such as macular degeneration, glaucoma, diabetes, Alzheimer disease, etc.), aging and drug use.

Therefore, even if we pass the flowers and green test cards smoothly, we cannot take it lightly, and the color blindness is not completely away from us. Scientific eyes can extend the "business hours" of our eyes as much as possible. Of course, if you find that you have color blindness or reduce the symptoms of color consciousness, you can seek medical treatment as soon as possible. references

[1] https://www.colour-blindness.com/colour-blindness-tests/ishihara- collect-plates/

[2] https://www.nhs.uk/Conditions/Colour- Vision-deficience/

[3] Birch, Jennifer (2012) .WORLDWIDE PREVALENCE of Red-Green Color Deface.

[4] http://leftSidepains.com/hemophilia/10/10/

[5] Basta M, pandya am. Genetics, x-linked inheritance. 2021 May 8. In: Statpearls [Internet]. Treasure Island (FL): Statpearls Publicishing; 2022 Jan-. Pmid: 32491315.

[6] Elshazly h. Optimizing bioinformatics variant analysis pipeline for clinical use. 2016.

[7] https://www.genetics.edu.au/publications-nd-rources/facts-sheets/Fact-9-X-LINKED-Recessheritance

[8] https://www.aao.org/eye-health/diseases/what-s-color-blindness

Author: Wang Yuanjia, students of the 2021 Shanghai Science and Technology Museum of Science and Technology

Edit: Little Dingdang

Xie Xie: Qian Yishan, deputy chief physician of the Eye, Ear and Throat Hospital affiliated to Fudan University; He Xin, an associate researcher at the Shanghai Natural Museum (Shanghai Science and Technology Museum Branch), provides scientific guidance for this article.

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