The question refers to the following table, which compares the percent sequence homology of four different parts (two introns and two exons)of a gene that is found in five different eukaryotic species. Each part is numbered to indicate its distance from the promoter (for example, Intron I is the one closest to the promoter). The data reported for species A were obtained by comparing DNA from one member of species A to another member of species A.
% Sequence Homology
$$\begin{array} { | l | l | l | l | l | }
\hline \text { Species } & \text { Intron I } & \text { Exon I } & \text { Intron VI } & \text { Exon V } \
\hline \text { A } & 100 \% & 100 \% & 100 \% & 100 \% \
\hline \text { B } & 98 \% & 99 \% & 82 \% & 96 \% \
\hline \text { C} & 98 \% & 99 \% & 89 \% & 96 \% \
\hline \text { D } & 99 \% & 99 \% & 92 \% & 97 \% \
\hline \text { E } &98\%&99\%&80\%&94\%\
\hline
\end{array}$$
Based on the tabular data, and assuming that time advances vertically, which phylogenetic tree is the most likely depiction of the evolutionary relationships among these five species?

Question

The question refers to the following table, which compares the percent sequence homology of four different parts (two introns and two exons)of a gene that is found in five different eukaryotic species. Each part is numbered to indicate its distance from the promoter (for example, Intron I is the one closest to the promoter). The data reported for species A were obtained by comparing DNA from one member of species A to another member of species A.
% Sequence Homology
$$\begin{array} { | l | l | l | l | l | } 
\hline \text { Species } & \text { Intron I } & \text { Exon I } & \text { Intron VI } & \text { Exon V } \
\hline \text { A } & 100 \% & 100 \% & 100 \% & 100 \% \
\hline \text { B } & 98 \% & 99 \% & 82 \% & 96 \% \
\hline \text { C} & 98 \% & 99 \% & 89 \% & 96 \% \
\hline \text { D } & 99 \% & 99 \% & 92 \% & 97 \% \
\hline \text { E } &98\%&99\%&80\%&94\%\ 
\hline
\end{array}$$
Based on the tabular data, and assuming that time advances vertically, which phylogenetic tree is the most likely depiction of the evolutionary relationships among these five species?

Quizplus · Accepted Answer

To determine the most likely evolutionary relationship among the five species, we need to look for patterns of similarities and differences in the sequence homology percentages.

First, we notice that species A has 100% homology for all four gene parts. This suggests that species A is the ancestor of the other four species.

Next, we see that species D has the highest homology percentages for all four gene parts, followed closely by species B and C. This suggests that species D, B, and C are more closely related to each other than they are to species E.

Finally, we observe that species E has the lowest homology percentages for both introns, suggesting that it is the most distantly related to the other four species.

Putting all of these observations together, we can create a phylogenetic tree that shows the most likely evolutionary relationships among the five species. Choice D is the best option because it shows species A as the common ancestor, species D, B, and C as more closely related to each other, and species E as the most distantly related.

The Question Refers to the Following Table, Which Compares the Percent