First, autosomal dominant hereditary deafness
In two groups of chromosomes, as long as one group has deafness, it will show deafness. We can see some patterns.
1. If one parent is deaf, the probability of hearing loss of the child is 50%; If both parents are deaf, then the probability that the child is deaf is 75%.
2. The next generation of deaf children may still be deaf, and the next generation of women who are not deaf will no longer be genetically deaf.
There is no gender difference in this hereditary deafness.
Second, autosomal recessive hereditary deafness
The characteristic of this hereditary deafness is that only the chromosomes from both parents contain deafness information can they show deafness. If only one set of chromosomes has a problem, you won't be deaf and become a carrier. Also through the schematic diagram, we can find some laws. 1 If both parents are not deaf, but both parents are carriers, then the probability of their children being deaf is 25%, the probability of being carriers is so%, and the probability of being completely normal is 25. If one party is deaf and the other is normal, their children will not be deaf, but they are all carriers. If both parties are deaf, the probability that their children are deaf is 100%.
If deaf children marry normal people, their next generation will not be deaf, but they are all carriers. Whether a child who is not deaf will be deaf in the next generation depends on whether he (she) is a carrier and the situation of his (her) spouse, that is to say, a child who is not deaf may have deaf children in the next generation.
There is no gender difference in this kind of deafness.
Third, the sex-linked genetic emptiness.
As mentioned earlier, among the 23 pairs of human chromosomes, one pair of sex chromosomes is called sex chromosome. If the boarding factor is located on this pair of chromosomes L, it will be inherited. This kind of hereditary deafness is called sex-related hereditary deafness. This kind of deafness is characterized by obvious gender differences in the occurrence of deafness in a family. In the whole hereditary deafness, the proportion of this kind of deafness is very small, about 1%.
Four, polygenic hereditary deafness and chromosomal abnormality deafness
Polygenic deafness is difficult to distinguish from deafness caused by environmental factors. Streptomycin-induced deafness has obvious family susceptibility, and some people think that this family susceptibility belongs to polygenic inheritance. Many cases of chromosomal abnormal deafness have mental and other developmental disorders, which are easy to find in clinic. In addition, this kind of deafness can be found through laboratory examination. In the above four cases, the first three are mostly road-borne deafness.
Through the above analysis, we can also understand the reason why deaf-mute children are more likely to appear in consanguineous marriage, that is, because of the close blood relationship between men and women, the possibility of having chromosomes with the same characteristics is much greater than that of non-consanguineous marriage. The probability of harmful chromosome combinations is also much higher. According to theoretical analysis, cousins are 78 times more likely to get married and have a deaf girl. Therefore, the marriage of close relatives should be strictly prohibited to ensure eugenics.
I wonder if you have a boyfriend? If you are not advised to find a boy who is far away from you, for example, if you are from the south, you'd better find a boyfriend from the north. Medically speaking, genes are complementary, which is better for eugenics! Also, it is best for both parties to have a systematic premarital examination before marriage!