The human genome contains a large number of pseudogenes. How would you distinguish whether a particular sequence encodes a gene or a pseudogene? How do pseudogenes arise?

Key Concepts

Gene vs. Pseudogene

A gene is a sequence of DNA that contains the instructions for synthesizing proteins, while a pseudogene is a non-functional segment of DNA that resembles a gene but has lost its ability to code for proteins due to mutations. Distinguishing between the two involves analyzing sequence conservation, presence of regulatory elements, and functional assays to determine if the sequence can produce a functional product.

Mechanisms of Pseudogene Formation

Pseudogenes can arise through several mechanisms, including gene duplication, where an extra copy of a gene is created and subsequently mutated, or retrotransposition, where mRNA is reverse-transcribed and integrated back into the genome. These processes often lead to the accumulation of mutations that render the pseudogene non-functional.

Functional Analysis Techniques

To determine if a sequence encodes a gene or a pseudogene, researchers employ various functional analysis techniques such as RNA sequencing to assess expression levels, and protein assays to check for functional protein production. These methods help clarify whether a sequence is actively contributing to cellular functions or is merely a remnant of evolutionary history.