GENOMICSAnushi JainMSc Part I

Roll No. :12Paper II

WHAT IS GENOMICS?Genomics is an area within genetics that

concerns the sequencing and analysis of an organism’s genome.

It involves the study of all genes at the DNA, mRNA, and proteome level as well as the cellular or tissue level.

The term genomics was first coined in 1986 by Tom Roderick, a geneticist at the Jackson Laboratory in Maine, during a meeting about the mapping of the human genome.

Genomics is the study of all genes present in an organism.

By definition, it can be defined as “A discipline in genetics that applies recombinant DNA,DNA sequencing methods and bioinformatics to sequence, assemble and analyze the structure and function of genomes.”

It includes studies of intragenomic phenomena such as heterosis, epistasis, pleiotropy and other interactions between loci and alleles within the genomes.

HISTORYGenomics is a concept that was first

developed by Fred Sanger in early 1970s, who first sequenced the complete genome of a virus and of a mitochondrion.

In 1972, Walter Fiers and his research group became the first to sequence a gene. They sequenced the gene of Bacteriophage MS2.

In 1995, Hamilton O. Smith and his team became the first to sequence a genome of a free living organism – that of Haemophilus influenzae.

GENETICS VS. GENOMICS

GENETICS GENOMICSGenetics is the study

of heredity.

“Gene" refers to a specific sequence of DNA on a single chromosome.

Genetics involves the study of functions and composition of the single gene.

Genomics is the study of the entirety of an organism’s genes.

“Genome” refers to an organism's entire genetic makeup.

Genomics addresses all genes and their inter relationships.

SUBFIELDS OF GENOMICSThe different research areas of genomics

can be as follows :

1. Structural Genomics2. Functional Genomics3. Comparative Genomics

GOALSThe main goal of genomics is to :

Sequence the entire genome by cutting it into small, manageable pieces (fragments).

Assemble the entire genome from the pieces (fragments).

Understand how gene expression takes place.

WHY TO SEQUENCE GENOMES?Sequencing genomes helps understand

how the genome as a whole and how the genes work together to direct the growth, development and maintenance of an entire organism.

The genome sequence will represent a valuable shortcut, thus helping to find genes much more easily and quickly.

TECHNICAL FOUNDATIONS The technical foundation of genomics

involves :Construction of Genomic and cDNA

librariesDNA HybridizationRestriction-enzyme mappingDNA sequencingPCR amplification

STEPS IN GENOME SEQUENCING Break genome into smaller fragments Sequence those smaller pieces Piece the sequences of the short

fragments togetherGENOME SEQUENCING APPROACHES

1. Hierarchical shotgun sequencing -Useful for sequencing genomes of higher

vertebrates that contain repetitive sequences.2. Whole genome Shotgun Sequencing -Useful for smaller genomes.

HUMAN GENOME PROJECTThe Human Genome Project (HGP) is an

international scientific research project with the goal of determining the sequence of chemical base pairs which make up human DNA, and of identifying and mapping all of the genes of the human genome from both a physical and functional standpoint.

HGP was formally founded in 1990 by the US Department of Energy and the National Institute of Health and was declared completed on 14th April,2003.

The basic goals of HGP were : To indentify all the genes and their

functions in a human DNA.To determine the sequences of 3 million

base pairs the makeup the human DNA.To develop tools for data analysis.To obtain physical map of human

genome.To store the information in public

databases.

BENEFITS & APPLICATIONSGenomics can be useful in following ways :

It can be used in the field of medicine for early detection of genetic diseases and its diagnosis and treatment.

It is also useful in the field of agriculture.To study evolution through mutation

lineages.In forensic science.

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