Multiple Choice
The different genes that code for the photoreceptive proteins that function in the vertebrate eye are all believed to be paralogs. Which statement below is most consistent with this idea?
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25. Phylogeny
Phylogenetics and Genome Evolution
Multiple Choice
Which of the following statements about homologs are true?
I) Phylogenetic trees of different taxa can be made using orthologs but not paralogs.
II) A gene family is a group of paralogs within a genome.
III) Orthologs are homologs that are found in different species.
A
I & II.
B
I & III.
C
II & III.
D
I, II, & III.
Verified step by step guidance1
Understand the concept of homologs: Homologs are genes related by descent from a common ancestral DNA sequence. They can be classified into orthologs and paralogs.
Clarify orthologs: Orthologs are homologous genes found in different species that have evolved from a common ancestral gene by speciation. They often retain the same function across species.
Clarify paralogs: Paralogs are homologous genes within the same species that have arisen by gene duplication. They may evolve new functions.
Evaluate statement I: Phylogenetic trees can be constructed using orthologs because they reflect evolutionary relationships between species. Paralogs, being within the same species, do not provide interspecies evolutionary information.
Evaluate statements II and III: A gene family consists of paralogs within a genome, and orthologs are indeed homologs found in different species. Both statements are true.
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