58 nucleotide differences 102 nucleotide differences 110 nuc

58 nucleotide differences

102 nucleotide differences

110 nucleotide differences

?

Your marine biology instructor tells your that on a particular homologous gene, bottlenose dolphins (Odon toccatas) and Right whales (Masticates) have 80 nucleotide differences. Based on that information and the phylogenetic tree below, how many nucleotide differences do you expect between Right whales and hippopotamus?

Solution

The dolphins and Right whales share a common ancester and therefore are the sister groups. Two sister groups in a phylogenetic tree are most closely related to each other. The branched points indicate the outgroups. Since hippo is present very far from dolphins and Right whales, as a outgroup, in the given phylogenetic tree; it should exhibit maximum difference in the mentioned gene. So, the correct answer among the given options is 110 nucleotides differences.