Genome Sequencing

The process of genome sequencing is very important in modern biotechnology. All organisms have a fixed number of chromosomes, which are usually of different structures or types.

A set of chromosomes in the nucleus of a species is called the genome. A haploid nucleus contains one genome, whereas a diploid nucleus contains two genomes. All human cells have 23 pairs of chromosomes. Each pair together makes up the entire human genome, which is why all human cells contain a pair of genomes.

Nobel Prize in Genome Editing

French scientist Emmanuel Carpenter and American scientist Jennifer Doudna were honored with the 2020 Nobel Prize in Chemistry for their pioneering work in genome editing. The technology, called CRISPR-Cas9 (Trisper Cass Nile Genetic Scissors), allows scientists to make specific changes in the DNA of living cells.

DNA and the Genome

DNA is the main component of chromosomes, and parts of DNA act as genes. Therefore, the complete DNA of an organism, containing all its genes in a set of chromosomes, is called the genome. The genome is often referred to as the organism's “master blueprint”.

DNA molecules are made of nucleotides, each consisting of:

• A sugar

• A nitrogenous base (Adenine = A, Guanine = G, Thymine = T, Cytosine = C)

• A phosphate group

The order of these bases along the DNA molecule is called the genome sequence. Determining this sequence is known as genome sequencing or DNA sequencing.

DNA Sequencing Process

Genome sequencing requires advanced technology and specialized equipment. DNA molecules are cut into fragments, sequenced, and then assembled.

• Originator: Dr. F. Sanger, Nobel Prize recipient

• Stages of genome sequencing:

  1. Separate DNA molecules into four test tubes containing reagents to detect A, T, G, C residues.

  2. Conduct gel electrophoresis to separate reactions and determine sequence from radioactive bands.

  3. Analyze results using a computer-controlled X-ray scanner.

Applications in Jute Genome

Bangladeshi scientist Dr. Maqsudul Alam and his team sequenced the genome of Tosha jute (Corchorus olitorius). They analyzed 12 billion base pairs, revealing the genetic makeup of jute.

• Potential applications include:

  • Fine fiber jute

  • Winter-resistant jute

  • Easily decomposable jute

  • Insect-resistant jute

  • Medicinal jute

  • Strong fiber jute like cotton

Dr. Maqsudul Alam recently passed away, leaving a lasting contribution to biotechnology.

Crop Disease Virus Genome Sequencing

• Yellow Mosaic Virus in pulses (Bangladesh):

  • Led by Prof. Muhammad Nurul Islam, Dhaka University

  • Sequenced the genome of yellow mosaic virus

  • Developing virus-resistant varieties using RNAi methods

• Tomato Leaf Curl Virus (ToLCV):

  • Genome sequenced with support from ICGEB

  • Developing tomato varieties resistant to ToLCV

• Novel Coronavirus (Bangladesh):

  • Genome sequenced by scientists from Bangladesh Council of Scientific and Industrial Research (BCSIR) and other institutions