An example of a polygenic trait is human skin color variation. Several genes factor into determining a person's natural skin color, so modifying only one of those genes can change skin color slightly or in some cases, such as for SLC24A5, moderately.
Case 1 â The Alleged Father has Recently Passed Away. If less than a week has passed since the deceased died, then if permission can be obtained, fingernail cuttings and a hair sample with root attached can be used to extract DNA samples to establish paternity. It is a more complex procedure than a buccal swab, but the DNA matching is just as accurate.
STR DNA, which is used for human identification, is extracted from nucleated cells. The ability to obtain reliable DNA profiles from fingerprints depends on the number of nucleated cells collected from the fingerprints. The more cells there are in a stain or on a surface, the more DNA there will be. If there are very few cells available, it is referred to as low copy number DNA profiling..