In the globin gene family shown in Figure 16.16, which pair of genes would exhibit a higher level of sequence similarity, the human δ-globin and human β-globin genes or the human β-globin and chimpanzee β-globin genes? Can you explain your answer in terms of timing of gene duplications?

Key Concepts

Gene Duplication

Gene duplication is a process where a segment of DNA is copied, resulting in two identical or similar genes. This can lead to genetic diversity and the evolution of new functions. Understanding the timing of these duplications is crucial, as genes that have diverged more recently will typically show higher sequence similarity due to less time for mutations to accumulate.

Sequence Similarity

Sequence similarity refers to the degree to which two DNA or protein sequences resemble each other. It is often measured by comparing the nucleotide or amino acid sequences to identify conserved regions. Higher sequence similarity usually indicates a closer evolutionary relationship or more recent common ancestry, which is essential for analyzing the relationships between the globin genes in humans and chimpanzees.

Phylogenetic Relationships

Phylogenetic relationships describe the evolutionary connections between different species or genes based on their genetic similarities and differences. By constructing phylogenetic trees, scientists can infer the timing of gene duplications and speciation events. In the context of the globin gene family, understanding these relationships helps determine which gene pairs are more closely related and why.