Which one of the following statements is correct?
Select one:
A. According to the divergent evolution model, all members of a gene family evolve in a coordinated manner rather than independently.
B. According to the divergent evolution model, members of a gene family gradually diverge as the duplicate genes assume new functions.
C. According to the birth-and-death evolution model, all members of a gene family evolve in a coordinated manner rather than independently.
D. According to the concerted evolution model, some gene duplicates remain in the genome while others are inactivated or deleted.
The correct answer and explanation is:
The correct answer is:
B. According to the divergent evolution model, members of a gene family gradually diverge as the duplicate genes assume new functions.
Explanation:
Divergent evolution occurs when gene families, which are typically the result of gene duplication events, evolve independently over time. In this model, the duplicate genes accumulate mutations and start to take on distinct functions. Initially, when genes are duplicated, they can serve the same role as the original gene, but over time, some duplicates will undergo changes that allow them to specialize or develop new functions. This diversification of gene functions enables organisms to adapt to a wide variety of environments and ecological niches.
The key characteristic of divergent evolution is that gene duplicates diverge from one another functionally and structurally. This can lead to the creation of gene families with specialized functions, such as different types of hemoglobin in different tissues, or enzymes that specialize in metabolizing different substrates.
In contrast to the divergent evolution model, the birth-and-death evolution model (C) involves genes evolving independently with some being retained in the genome while others are deleted or become non-functional. This model does not describe coordinated or gradual changes within a gene family.
The concerted evolution model (D) involves gene duplicates evolving in a coordinated manner. This means that they remain similar to each other and evolve together as a group. In this model, some gene copies may be deleted, but the overall coordination prevents divergence in function.
Thus, option B best describes the process of divergent evolution, where duplicate genes gradually diverge as they take on new functions over time.