Post Date December, 03 2023
Homosexuality has changed its previously secretive underground state and gradually entered the public eye. Countries such as the United States have already legislated to allow same-sex marriage, but with the legalization of same-sex marriage, a question arises: is homosexuality truly genetically exclusive?
Because many states in the United States have successively recognized homosexual marriage, which has led to further openness of homosexuality, there has been a heated issue for decades, which is whether there is a homosexual gene.
American Scientists Discovering Homosexuality Genes
The scientist who first identified homosexual genes was American geneticist Dean Hamer. When studying homosexual populations, he found that if a family has several homosexuals, they often come from the maternal line. Therefore, he believed that a certain gene on the X chromosome affects homosexual orientation. Based on the X chromosome of homosexual siblings, he discovered that a gene at the top, Xq28, determines homosexuality.
After this paper was published in Science, Hamer became a controversial figure, and there was a lot of opposition to his results. Those who hold traditional views naturally strongly oppose it, and the homosexual population is also divided into two factions. One faction is happy because there is finally evidence that it is not their own fault, while the other faction is worried because at that time, society was still in a state of overall discrimination against homosexuality. They are worried that this will lead to the emergence of homosexuality testing laws, further exacerbating social discrimination and unfairness towards them. Several studies later supported Hamer's conclusion, and homosexual genes were also found on three other chromosomes.
Gay gene research has flaws
At the beginning of this year, a large study conducted by Northwestern University in the United States found that the DNA of 400 homosexuals could not accurately predict homosexuality through the Xq28 gene. However, it was found that there is a homosexual gene on chromosome 8, which cannot be accurately predicted.
Both the positive and negative sides have a say in this result. Traditional forces believe that this indicates that homosexuality is still influenced by the environment and society. Since homosexuality is not born but a personal choice, the legalization of homosexuality is untenable, because homosexuality is not conducive to human health from the perspective of high incidence of diseases among homosexual people such as AIDS. The side that supports homosexual genes points out that homosexual genes do not appear to be single, but are determined by many genes, just like height.
Molecular biology research has neither confirmed nor denied the existence of homosexual genes, while observations from the animal kingdom tend to acknowledge the prevalence of homosexuality in the animal kingdom. Moreover, genetic modification of fruit flies can make them homosexual, providing animal experimental evidence for the existence of homoerotic genes.
Why can homosexual genes be passed down
The proportion of homosexuality in the population is between 5% and 15%. If there are indeed homosexual genes, it seems difficult to explain from an evolutionary perspective because homosexuality does not have offspring, and these genes will not be passed down, let alone such a large proportion. This gene is not conducive to human reproduction and should be eliminated by evolution.
One explanation for the existence of this high proportion of homosexuality is that it is a genetically significant human behavior, citing sickle cell anemia as an example. In ancient times, falciparum malaria was rampant in Africa, with high mortality rates, forcing humans to respond genetically, resulting in a genetic mutation called sickle cell anemia that targets malaria. It's a genetic disease, globin β A single base mutation occurs in the chain gene. normal β The sixth codon of the gene is GAG, encoded as glutamate, mutated into GTG, encoded as valine, making it abnormal hemoglobin S (HbS), and the cell changes from a normal double concave disc shape to a sickle shape. If a child inherits an abnormal gene from both parents, sickle cell anemia will occur. If a child inherits an abnormal gene from only one parent, there will be no symptoms, but the abnormal gene will be passed on to the next generation.
Sickle cell anemia has a protective effect on falciparum malaria. The mononuclear phagocytic system will eliminate sickle cells along with the malaria parasite, which can reduce the mortality rate of falciparum malaria by 90%. But 25% of infants with sickle cell anemia will die, and the mortality rate of first-time pregnant women is also higher. For Africans, it is worthwhile to trade this maternal and infant mortality rate for protection against falciparum malaria. This gene mutation has spread in areas where falciparum malaria is prevalent, and up to 40% of people in Africa, South Asia, and the Middle East have this gene mutation.
The Biological Practical Use of Homosexuality Genes
Returning to homosexual genes, experts from the supporting side believe that this is a "male loving gene", mainly used to make women with these genes mature earlier in terms of sex, thus enabling them to have more children and thus have evolutionary advantages. The cost is that if men have these genes, they will become homosexual. This theory is supported by evidence, as research conducted in Italy found that female relatives of homosexual men have 1.3 times more children than other women. This is a huge advantage in selection, at the cost of male relatives being homosexual. In contrast, the benefits outweigh the drawbacks, so it has been selected by evolution and passed down through the X chromosome generation by generation.
Similarly, men should also have a "love for women gene", which is an evolutionary advantage in men and will have more offspring. However, in women, being a lesbian also has more benefits than disadvantages, allowing them to inherit. This "female loving gene" can not be inherited through sex chromosome, but on other chromosomes, so lesbians are not as numerous as gay, and the proportion of bisexuals is large.
There is another theory that can explain the pros and cons, which is an example of citing height. Height is determined by multiple genes, and how tall one can grow depends on the combination of various genes and the actual situation, which is unpredictable. Homosexuality is likely to be the same. In addition to the Xq28 on the X chromosome, there are also other "male loving genes", as well as "female loving genes". Each person's body has these two genes, and there may be a total of tens of thousands of genes in the population.
Special genes and acquired environmental impacts
Each person inherits these two genes with different combinations, and then there are environmental and developmental influences, making the situation unpredictable. If a certain "male loving gene" dominates men, it is gay. A certain "love for women gene" dominates in women, which is lesbian. The degree of dominance determines the severity of homosexuality tendencies. Most people are neither dominant, so most people are heterosexuality.
This explains why shared genes can be found in homosexual populations, but it is not possible to predict homosexuality based on these genes. The emergence of homosexuality is likely a joint result of both innate and acquired factors.
Homosexuality genes should exist, but they are not limited to homosexual populations. We all have this gene, gay and lesbian are just two extremes.
