Question

1. Give a complete, all-encompassing definition of a gene. Discuss each part of your definition. Is the definition of the gene as determined through complementation, recombination, and mutation for prokaryotes directly applicable to eukaryotes or must some additional considerations be taken into account? Explain.

Answer 1

An all encompassing definition of a gene would :

"Gene is the discrete unit of heridity that is made up of DNA ,interspersed along with junk DNA and that encodes for functional product molecules i.e either RNA or protein molecules that function to influence phenotypes in various ways and being regulated by regulatory elements. Genes are part of DNA that encode for RNA molecule that goes on to produce a protein.Genes produce an RNA molecule and a protein under the influence of regulatory sequences such as operons( as seen in prokaryotes) and enhancers and silencers(as seen in eukaryotes).These proteins function to determine various phenotypes both qualitatively and quantitatively.

Some additional considerations must be taken such as how of the processes that define gene work.For example, the process of recombination and mutation is very fast in prokaryotes in comparision to eukaryotes as a result of which prokaryotes evolve faster than eukaryotes. Also,the arrangement of genes varies i.e they are found as operons in prokaryotes but not in eukaryotes.While gene in prokaryotes produce a single mRNA molecule which codes for many polypeptides and is polycistronic ;the genes is eukaryotes produce a single mRNA molecule that codes for a single polypeptide and is monocistronic.