Darwin was a great biologist in the19th century and the founder of the theory of evolution. However, before he mastered the mystery of the natural biological world, he was mercilessly punished by the laws of nature.
1839 10 In October, 30-year-old Darwin married his cousin Emma. Emma is his uncle's daughter. The two of them have been childhood friends since childhood, and they have deep feelings and secretly love to get married.
However, none of them expected that three of their six children died young and the other three were infertile for life. This incident puzzled Darwin, because he and Emma were both healthy people, with no physical defects and normal spirits. Why are all children born like this?
When Darwin studied the biological evolution of plants in his later years, he found that cross-pollinated individuals produced larger and more fruits than self-pollinated individuals, while self-pollinated individuals were easily eliminated naturally. At this time, Darwin suddenly realized that nature hates consanguineous marriage.
Darwin realized that the tragedy of his marriage lies in close relatives, so he wrote this profound lesson in his paper.
Morgan, a famous American geneticist who founded the "gene" theory in this century, also had a marriage that should not have appeared. After he married his cousin Mary, he made outstanding achievements in scientific research. The book Biography of Morgan written by later generations said: "Morgan's success in his career cannot be separated from Mary's help." However, their two daughters were "inexplicably demented" and left this world prematurely. Their only boy also has obvious mental disability.
Mr. and Mrs. Morgan have no more children. He proposed: "Marriage between unrelated ethnic groups can create a more physically and intellectually robust race." He shouted: "In order to create a smarter and stronger race, under no circumstances should you marry a close relative."
Human germ cells, that is, male sperm and female eggs, have 23 chromosomes with 65438+ million "genes" on them. Genes carry the "code" of life inheritance.
It is estimated that among the 654.38+10,000 genes, there will always be five or six hidden genetic disease genes. As long as it is not consanguineous marriage, it is difficult for both men and women to encounter pathogenic genes. Among close relatives, this more opportunity makes them face to face. For example, there is a genetic disease called galactosemia, and the incidence rate is 1/90000, that is, only one patient can appear in 90000 couples. In the crowd where cousins get married, the risk of children getting sick is 1/4800, which is 8 times that of the former. A survey of 5,227 children born of 3,355 local three-generation consanguineous marriages in a certain place in Jiangsu Province shows that as many as 880 people (about 17%) suffer from various congenital or hereditary diseases, among which 98 people have mental retardation, which is far greater than the incidence of children born of non-consanguineous marriages in the same area.