Difference Between Gene Mapping and Gene Sequencing

The key difference between gene mapping and gene sequencing is that gene mapping is a technique that identifies the location of a gene in the genome and the distances between genes while gene sequencing is a technique that identifies the precise order of nucleotides of a gene.

Gene mapping and gene sequencing are important in genetic diagnostics to locate and confirm the presence of genes. Thus, molecular techniques such as gel electrophoresis and polymerase chain reaction, play important roles in deducing a gene map. Furthermore, the usage of different sequencing techniques such as Sanger sequencing and Next-Generation sequencing is essential to generate a gene sequence.

CONTENTS

1. Overview and Key Difference
2. What is Gene Mapping 
3. What is Gene Sequencing
4. Similarities Between Gene Mapping and Gene Sequencing
5. Side by Side Comparison – Gene Mapping vs Gene Sequencing in Tabular Form
6. Summary

What is Gene Mapping?

Gene mapping is the technique of generating a complete map of the locations of genes in a chromosome. Chromosome mapping is a synonym for gene mapping. Further, this technique provides information about the specific genes located in the chromosome. Moreover, gene mapping uses physical mapping methods during the mapping process.

Gene mapping can help to find chromosomal aberrations. Therefore, the genetic map acts as a diagnostic tool to detect conditions such as Downs syndrome and Turners syndrome, etc. Karyotyping is one technique that can be used to generate a genetic map. Staining is an important technique in generating a genetic map where stains such as ethidium bromide, acridine orange and Giemsa are used. Gene mapping can also generate linkage maps where identification of the location of the linked genes takes place.

What is Gene Sequencing?

Gene sequencing is the technique used to identify and deduce the precise base pair sequence of the gene. Thus, through gene sequencing, one can deduce the order of adenine, guanine, thymine and cytosine bases in a sequence. The first whole-genome sequencing took place in microorganisms. The human genome sequencing project was one of the turning points of the history of molecular biology. At present, gene sequencing plays an important role in industry and medical fields. This precisely confirms the presence of a particular gene in the genome.

There are different techniques to sequence a gene. Maxam and Gilbert were the pioneers of introducing a chemical method to sequence genes or DNA. However, the use of potentially hazardous chemicals leads to the abandonment of the chemical sequencing technique. Later, Sanger introduced a sequencing technique that did not use any hazardous chemicals. However, at present, automated sequencing and next-generation sequencing play important roles in deducing the sequence of a particular gene.

What are the Similarities Between Gene Mapping and Gene Sequencing?

• Both techniques play important roles in genetic diagnostics.
• These techniques have the ability to confirm the presence of genes in the genome.
• Techniques such as polymerase chain reaction can be used in both processes.

What is the Difference Between Gene Mapping and Gene Sequencing?

The key difference between gene mapping and gene sequencing is the information the two techniques generate. Gene mapping provides information on the location of a particular gene in a chromosome while gene sequencing generates information regarding the sequence of base pairs of a particular gene. However, both techniques play a role in the characterization of a gene. Thus, the time and the cost taken for the completion of the two techniques differ.

The below infographic summarizes the difference between gene mapping and gene sequencing.

Summary – Gene Mapping vs Gene Sequencing

Gene mapping and gene sequencing are two techniques that help in characterizing a gene. While a gene map enables locating the gene, the gene sequence provides the biochemical data of that particular gene. Gene mapping and gene sequencing are very important in genetic studies and genetic diagnostics. Moreover, both techniques are now automated to ensure that the techniques are rapid and accurate. The information generated through gene mapping and gene sequencing is used in downstream processes during molecular diagnostics.

Reference:

1. Brown, Terence A. “Mapping Genomes.” Genomes. 2nd Edition., U.S. National Library of Medicine, 1 Jan. 1970, Available here.
2. “DNA Sequencing Technologies”  Nature News, Nature Publishing Group, Available here.

Image Courtesy:

1. “NHGRI Fact Sheet- Genetic Mapping (27058469495)” By National Human Genome Research Institute (NHGRI) from Bethesda, MD, USA – NHGRI Fact Sheet: Genetic Mapping (CC BY 2.0) via Commons Wikimedia
2. “154044” (CC0) via Pixabay