rlh@cvl.UUCP (Ralph L. Hartley) (10/19/84)
> This was for the amino acid sequences for the alpha hemoglobins of a > viper, crocodile, and a chicken. (The two reptiles should be closest). Why? Acording to the standard theory birds (and mamals) have a reptile ancestor. In particular Archeoptrix (spelling) - which may or may not be a direct ancestor of modern birds - has characteristics of both birds and dinosaurs. There is still argument about which groop it should be clasified with, but the bottom line is that it is both. In any case I would expect the bird to be closer to the crocodile, but not by much. > But of the amino acids in common, it is the crocodile and chicken > (17.5%), next the viper and chicken (10.5%) and last the two reptiles > (5.6%). An examination of the amino acids in myoglobin shows > crocodiles and lizards share 10.5%, while the crocodile and chicken I think you mean snakes. > share only 8.5%. *But* the lizard and chicken also share 10.5% - the > same as the reptile/reptile pair. What are the confidence intervals on these numbers? Remember that changes are random and that with a small sample (one protien) this will add noise to the pattern. > In the case of DNA, we should expect a 25% match (since there are only > 4 possibilities for each position), yet among 5 presumably closely > related species (man, chimpanzee, gorilla, orangutan, and gibbon) there > was only a 7% match. Do you have your facts right? It is imposible to devise 5 strings from a 4 letter alphabet without at least a 20% match. This is a mathematical fact! For each letter at least two of the strings must match. Ralph Hartley rlh@cvl seismo!rlgvax!cvl!rlh