There is a very complex relationship between genes, traits and diseases. the most primitive way to decipher this relationship is the gene linkage analysis established in the middle of the last century: by comparing the similarities and differences of chromosome bands or genetic markers of different members of families affected by genetic diseases, locate disease-causing genes on chromosomes. This method has made a lot of achievements in the study of single-gene genetic diseases, but its disadvantage is that the resolution is limited
it is difficult to accurately locate a single gene.
It is difficult to accurately decipher the relationship between genes and diseases