DNA Sequencing

In news: An international team of scientists have completed the genome sequencing of the wild brown trout — one of the most genetically diverse group of vertebrates.

• It is part of an ambitious project to track the DNA of tens of thousands of lifeforms in the United Kingdom.
• It will answer a long-standing debate about whether they are a single species or several.

Brown trout:

• Also called, Salmo Trutta, it has only 3 to 50 species.
• It has 38 to 40 chromosomes and multiple copies of those chromosomes within its genome.

DNA Sequencing:

• DNA sequencing is the process of determining the nucleotide sequence of DNA (deoxyribonucleic acid).
• DNA is made up of four chemical building blocks – called “bases” – adenine, guanine, cytosine, and thymine.
• It involves determining the sequence of these bases which encodes the biological information that cells use to develop and operate.
• The nucleotide sequence is the most fundamental level of knowledge of a gene or genome. It is the blueprint that contains the instructions for building an organism.
• Human genome contains about 3 billion base pairs that spell out the instructions for making and maintaining a human being.
• DNA sequencing methods:

• Maxam-Gilbert sequencing
• Chain-termination methods
• Shotgun sequencing
• Single molecule real time (SMRT) sequencing
• Nanopore DNA sequencing

• In India, Next Generation Sequencing (NGS) facilities are available; which are also represented in the Indian SARS-CoV -2 Genomics Consortium (INSACOG).

Significance:

• Identify genetic traits that helped the species cope with environmental pressures, help trout adapt to relatively acidic waters and boost wildlife conservation during climate change.
• Learn about how trout adapt to different conditions, helping the management of wild and farmed fish stocks in future.
• Reveal the mythical ‘superpowers’ of the iconic brown trout that made them one of the first species to recolonise previously frozen freshwater areas from the sea at the end of the last Ice Age.
• Their unique genetic adaptations helped different populations to exploit biological niches, with some living their whole lives within a 200-metre stretch of freshwater stream while others migrate from the stream to the open sea.

Source: Down to Earth

Previous Year Question

Q1.) Consider the following statements : DNA Barcoding can be a tool to : (2022)

1. assess the age of a plant or animal.
2. distinguish among species that look alike.
3. identify undesirable animal or plant materials in processed foods.

Which of the statements given above is/are correct?

1. 1 only
2. 3 only
3. 1 and 2
4. 2 and 3