Hi.

I am studying the proteins ("A") found commonly in the same tribe.

However, there is a exception so that "A" is not found in one genus in the tribe. Instead of "A" protein, the other protein (B) is found in only that genus. Both "A" and "B" are similar in some functional side, but their sequence length and the chromosome locations of their genes are different.

Some researchers mentioned that "B" have no analogues in others, but others mentioned "B" is an orthologue of "A" without any reference so that I am confused. Most of researchers have no interest in the relationship between "A" and "B". In most of research articles, they are studied separately, and the articles that treat both of them are mainly review papers.

The nucleotide and protein sequences of both "A" and "B" have been analyzed and can be obtained at NCBI databases. Using this data, I want to proof that "B" is an orthologue of "A", and "B" has been changed from "A" because of an evolutionary process.

However, I don't know the suitable methods, so I want to read some related articles but I can't find it. Can you recommend some articles related to the ortholog proteins?