Scientists publish evolutionary trees all the time in which they compare the DNA of individual people. They also use the same methods to demonstrate that chimpanzees are our closest living relatives, that primates descend from small shrew-like mammal ancestors, that mammals and other land vertebrates descend from fish, and so on. (I don’t have time this morning to grab examples of these trees, but if I have time tonight I will.) Certainly there are parts of these trees that are still difficult to make out. DNA sometimes evolves so much that a gene can wind up obscuring its own history, for example. But scientists have never hit the wall that creationists claim exists.
It’s difficult when you have to fight ignorance coupled with extreme cognitive dissonance, a potent and frustrating mix.