What are the genetic differences between a processed pseudogene and a mutated pseudogene and how do their typical locations relative to their functional paralogous genes differ? Solution Pseudogenes are the genes that have lost some part or entire of its original ability, of their real gene relative and thus they have a altered or no gene expression activity. Most commonly, pseudogenes are formed as a result of accumulation of multiple mutations in a single gene, whose gene product is not essential for survival. Pseudogenes may not be fully functional and may perform regulatory functions. Thus a pseudogene has its association with a functional gene, and both of them share a common ancestor. Processed pseudogenes are the result of retrotransposition, i.e, a part of the mRNA or hnRNA transcript from a gene spontaneously reverses back (transcribed again) into DNA and gets inserted into chromosomal DNA.Thus they are processed once and then reverses back to result in a pseudogene. As a result, random copies of genes are produced in vitro. When such pseudogenes are inserted into the genome, they usually contain a poly-A tail,they are without introns (introns are spliced out) and also lack the upstream promoters. Thus after transposition event, they become non-functional pseudogenes. Such pseudogenes are randomly inserted into the genome. On the other hand, mutated pseudogenes arise after multiple mutation events which prevent a gene from normal transcription and make them less functional or non-functional; like gene duplication event caused by homologous recombination (repititive sequences on misaligned chromosomes become non-functional) or one allele of gene having deleterious mutation resulting in loss of function, non-sense mutations, unequal cross overs and sister chromatid exchanges etc. In such pseudogenes, the location of genes remain same as their functional paralogous genes..

1. What are the genetic differences between a processed pseudogene and a mutated pseudogene and
how do their typical locations relative to their functional paralogous genes differ?
Solution
Pseudogenes are the genes that have lost some part or entire of its original ability, of their real
gene relative and thus they have a altered or no gene expression activity. Most commonly,
pseudogenes are formed as a result of accumulation of multiple mutations in a single gene,
whose gene product is not essential for survival. Pseudogenes may not be fully functional and
may perform regulatory functions. Thus a pseudogene has its association with a functional gene,
and both of them share a common ancestor.
Processed pseudogenes are the result of retrotransposition, i.e, a part of the mRNA or hnRNA
transcript from a gene spontaneously reverses back (transcribed again) into DNA and gets
inserted into chromosomal DNA.Thus they are processed once and then reverses back to result in
a pseudogene. As a result, random copies of genes are produced in vitro. When such
pseudogenes are inserted into the genome, they usually contain a poly-A tail,they are without
introns (introns are spliced out) and also lack the upstream promoters. Thus after transposition
event, they become non-functional pseudogenes. Such pseudogenes are randomly inserted into
the genome.
On the other hand, mutated pseudogenes arise after multiple mutation events which prevent a
gene from normal transcription and make them less functional or non-functional; like gene
duplication event caused by homologous recombination (repititive sequences on misaligned
chromosomes become non-functional) or one allele of gene having deleterious mutation resulting
in loss of function, non-sense mutations, unequal cross overs and sister chromatid exchanges etc.
In such pseudogenes, the location of genes remain same as their functional paralogous genes.