DNA is a long chain of nucleotides while a gene is a function piece of the DNA.
The DNA is made up of three important molecules deoxyribose sugar, phosphate, and nitrogenous bases.
DNA is an important molecule for life on earth in fact for all the lifeforms. However not all the DNA makes proteins but only genes can. In the present article, I will explain to you some of the major differences between DNA and gene.
I know for some, the comparison is irrelevant but for beginners, it is very important to understand what is DNA and what is a gene.
The gene itself is a sequence of DNA, there are some differences between the two though. To know the gene between we need to understand what the DNA is first!
DNA is a kind of nucleic acid and an inheritance unit for all of us. Their main function is to store and transfer biological information. Also, it transfers information to consecutive 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.
DNA vs Gene:
The function of DNA is to form proteins through the translation in which the transcribed intermediated mRNA forms a long chain of amino acids.
A protein is made from the function part of the DNA and works as a functional or structural entity of us.
Two types of DNA sequences are present in our genome, 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.
So 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 non-coding. On the other side, 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. A total of 23 pairs of chromosomes are present in us in which X and Y are sex chromosomes.
Interestingly, the genes are majorly located on the middle part of each chromosome (on the arms) while the other non-coding DNA is located on the 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 regions of a chromosome.
The repetitive DNA portion of a gene is lesser in comparison with the non-coding DNA. The genes aren’t so complex while the non-coding DNA re highly repetitive. In addition to this, the overall GC-content of non-coding DNA is very high.
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 has a definite function. The non-coding DNA sequences control the expression of genes.
The genes are unmethylated active DNA sequences that undergo transcription and translation while the non-coding DNA sequences are highly methylated sequences that can 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 that helps in the regulation of gene expression.
A gene can transcribe 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 to 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 and 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.
The repetitive nature of the DNA other than genes also facing problems during replication. Contrary, as the genes are less repetitive, it can smoothly replicate during cell division.
As in each replication cycle, some DNA sequences miss the replication and lose, thus after each round of replication some DNA sequences are lost and we age.
Related article: Role of telomere in aging.
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 bases in it.
“A gene transfers information for a specific trait while the DNA transfers all the information for all the traits as well as to regulate gene expression.”
These are some differences between gene and DNA and I think this will help 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: