A pseudogene is a Group of answer choices second copy of a gene that functions when the original copy becomes damaged. gene that is unrelated in sequence to another gene but has the same function. gene that evolved by gene duplication and the acquisition of mutations to yield a gene product that has a slightly different function from that of the original gene product. gene that arose through gene duplication, but by acquiring mutations became nonfunctional.

Gene that arose through gene duplication, but by acquiring mutations became nonfunctional.

Explanation:

A gene is a functional unit of heredity formed by DNA. They possess a sequence of nitrogenous bases that during translation is read by ribosomes to produce molecules called proteins.  A pseudogene is a DNA sequence that resembles a gene, but which has been inactivated in the course of evolution by mutations in its sequence. Thus, it is a gene that derives from other known genes and whose functions are different, may have lost their functionality or have radically changed it. To this day, it is not known exactly how pseudogenes are created, however some theories are as follows:

1. A gene duplication can generate two copies of a gene when only one is needed. A mutation would then occur that deactivates one of the copies. In addition, the duplication event may not be complete, so that the copy has incomplete promoters.  

2. They may be fragments of the messenger RNA transcript of a gene may be spontaneously reverse transcribed and inserted into the chromosomal DNA. They lack the promoters of normal genes, so they are not expressed normally.

3. A gene may become non-functional or inactivated if such a mutation becomes fixed in the population. This can occur by normal means such as natural selection or genetic drift.

this protocol describes a detailed procedure for intracellular flow cytometry staining.