Genes in different species that evolved from a common ancestral gene by speciation are called

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HPSC Assistant Professor 2018 Botany (Official Paper)

Answer 1

The correct answer is orthologs

Explanation:

Genes in different species that evolved from a common ancestral gene by speciation are known as orthologs.
Orthologous genes retain the same function in the course of evolution.
They are crucial for understanding the evolutionary relationships between species and for the functional annotation of genomes.
Homologs: These are genes related by descent from a common ancestral DNA sequence. Homologs can be further classified into orthologs and paralogs, depending on how they diverged. Thus, while all orthologs are homologs, not all homologs are orthologs.
Orthologs: Orthologs are genes in different species that evolved from a common ancestral gene by speciation. They typically have the same function across different species. For example, the hemoglobin genes in humans and mice are orthologs.
Paralogs: These are genes related by duplication within a genome. Paralogs often evolve new functions, even if related to the original one. For example, the human α-globin and β-globin genes are paralogs.
Pseudogenes: These are segments of DNA that resemble functional genes but have lost their gene expression ability or are no longer functional due to mutations. They are essentially "dead" genes that do not produce functional proteins.