A DNA is a long chain of nucleotides while a gene is a function piece of the DNA.
The DNA is made up of the three important molecules deoxyribose sugar, phosphate and the nitrogenous bases.
The DNA is an important biomolecule for life on earth while the gene is a function portion of it, in the present article, we will try to differentiate DNA vs Gene.
I know for some, the comparison is irrelevant but for beginners, it is very important to understand what is a DNA is and what is a gene.
Although the gene itself is a sequence of DNA, there are some differences between both but before we differentiate let’s understand what DNA is!!
The DNA is an organic biomolecule having all the information of us and inherited to the next generations.
A duplex or double-strand of DNA is bounded with each other with the hydrogen bonds- three between cytosine and guanine and two between adenine and thymine.
It is a polynucleotide chain made up of the nitrogenous bases adenine, thymine, guanine and thymine.
The DNA replicates and doubles each time during the cell division and thus it inherited from one cell to two daughter cells.
The function of DNA is to form proteins through the translation in which the transcribed intermediated mRNA forms a long chain of amino acid.
A protein is made from the function part of the DNA and work as a functional or structural entity of us.
Two type of DNA sequences are present in us, coding DNA sequence and non-coding DNA sequence.
Only 3% of DNA sequences are coding called genes while the non-coding DNA can not form any protein.
Thus even if a gene is a long chain of DNA, not all the DNA are genes- only a function piece of DNA is called a gene.
So the first and important difference between the DNA vs Gene is the functionality, the DNA may be coding or DNA coding polynucleotide sequences while a gene is only a protein-coding portion of it.
“DNA is like the entire book having all the information for us to live while a gene is like a single page from it having one specific information for one particular function.”
The second and another socking difference between DNA and gene are their location on a chromosome.
A chromosome is a complex network of DNA and protein. By interacting with the histone proteins DNA forms different chromosomes.
Total 23 pairs of chromosomes are present in us in which X and Y are sex chromosome.
Interestingly, the genes are majorly located on the middle part of each chromosome while the other non-coding DNA are location on telomeres and centromeric part of the chromosome.
Genes are located on “p” or “q” arms while the non-coding other DNA is located on the microsatellite and minisatellite region of chromosomes.
The genes are DNA sequences with fewer repeated-sequences or (nearly no repeated DNA) while the non-coding DNA sequences or sequences other than coding gene sequences are highly repeated DNA sequences with high GC content in it.
And as we discussed above the repeated DNA sequences are located either on microsatellite or minisatellite regions.
The genes encode a particular protein, however, the DNA (other than gene sequences) also have definite function. The non-coding DNA sequences control the expression of genes.
The genes are unmethylated active DNA sequences which undergo transcription and translation while the non-coding DNA sequences are highly methylated sequences undergo neither transcription nor translation.
Thus unable to form a protein.
Note: some non-coding DNA sequences can transcribe into a special type of RNA called microRNA helps in regulation of gene expression.
A gene transcribed into mRNA while the non-coding DNA can not transcribe into mRNA.
The packaging of gene sequences and other DNA sequences are also different, the function pieces of DNA- genes- are loosely packed allow access for expression while the non-coding DNA is tightly packed and methylated thus enzymes can not access those sequences for forming a protein.
Read our article on DNA packaging in eukaryotes.
Euchromatin is loosely packed function pieces of gene-rich regions stained light blue on staining with Giemsa while the heterochromatin regions are firmly packed regions of DNA stained dark blue on Giemsa staining.
Another important difference between both is- the end replication problem.
Some sequences remain unreplicated at the end of the replication, these sequences are located on the ends-telomeres- of the chromosomes.
Thus if important genes are located on ends, they miss the replication and that is the reason, the genes are located on the arms of the chromosomes, not on the ends of the chromosomes.
The repeated sequences of DNA facing the end replication problem, while the genes replicated properly after each cycle of replication.
As in each replication cycle, some DNA sequences misses the replication and lost, thus after each round of replication some DNA sequences are lost and we age.
Related article: Role of telomere in ageing.
Genes are made up of DNA or RNA while the DNA is made up of the long chain of polynucleotides with adenine, thymine, guanine and cytosine.
“A gene inherited information for a specific trait while the DNA inherited all the information for all the traits.”
These are some differences between gene and DNA and I think this will helps you to understand more about gene and DNA.
From our discussion, it is now clear that the gene has the hereditary information while the DNA has the genetic instructions.
We have also explained the difference between some other terms too. Read it here: