(2) Biological characters are mainly controlled by genes, but also influenced by environment. The local environmental factors are the reasons why the cotton imported from Xinjiang can't meet the expectations of the director of a cotton mill.
(3) As can be seen from the above table, the possibility of genetic diseases in the offspring of inbreeding is as follows: congenital deafness11500 >1∑1/800; It shows that the offspring of consanguineous marriage are more susceptible to genetic diseases than those of normal marriage, and the prevalence ratio is 8: 1. Close relatives refer to direct blood relatives and collateral blood relatives within three generations. China's marriage law has clearly stipulated that it is forbidden to marry lineal blood relatives and collateral blood relatives within three generations. Why? The reason is that close relatives are more likely to have the same recessive genetic disease-causing gene, and children born to close relatives are more likely to suffer from genetic diseases. For example, the incidence of single-gene recessive genetic disease of children born of consanguineous marriage is 7.8 ~ 62.5 times that of children born of non-consanguineous marriage, so the incidence of offspring of cousin marriage is much higher than that of offspring of non-consanguineous marriage.
So the answer is: (1) genetic material; Genetic variation; (2) Biological characters are influenced by environment; (3)8: 1; Cousins are likely to have the same recessive pathogenic gene, so the incidence of offspring is much higher than that of non-relatives.