UNIT 4 ... SEM 6

PAPER 1

MS. Swatantrata M. Sharma

GENETIC ENGINEERING

Introduction

Combination of Genetics & Engineering

GENETICS – It is the science that deals with the study of

heredity & variation

Heredity –Transmission of traits from parent to off spring

Variation – Similarities & differences

ENGINEERING- It is the application of knowledge in the

form of Science ,Maths to the innovation, design,

construction, operation & maintenance of structure,

machines, materials ,devices system, process & organization.

GENETIC ENGINEERS can alter the DNA code of living

organism

“Genetic Engineering is a technique, where genes are

transferred from one cell to another/ one organism to

another to produce recombinant DNA.”

This Recombinant DNA is used for the synthesis of valuable

products such as insulin , drugs etc

Scopes -

Synthesis of Drugs & other chemical.

Production of precious human hormones in large quantities by

implanting the gene in microorganisms

Cure of certain human molecular diseases by simple DNA

transfection.

Nutritional requirements of agriculturally important plants by

suitable gene transplant

Improvement of crop plants & domestic animals.

The DNA formed by joining DNA segments of two different

organisms is called recombinant DNA (r DNA) /

chimeric DNA.

The organism whose genetic makeup is manipulated using

recombinant DNA technique , is called recombinant /

Genetically Manipulated Organism.(GMO)

Enzymes :-

It is a substance, usually produced by plants & animals, which

helps a chemical change to happen more quickly, without

being changed itself.

The enzymes useful for cutting DNAs into pieces & again

joining the cut pieces into a long DNA are called Enzyme

tools of genetic engineering.

They are used to construct rDNAs for gene manipulation.

Restriction Enzyme , Ligases, DNA polymerase

RE are a special group of Nucleases which make specific cuts

on DNA strands to produce fragments.

Discovered by Lederberg & Meselson in 1964.

These are chemical Knives ( molecular scissors )

The RE are classified into 3 types ---Type I ,II, III

Type II recognize a specific nucleotide sequences & cleave it in

on near the vicinity of the recognition sequence.

The ability of an enzyme to recognize a particular sequence is

called Sequence specificity. The recognized sequence known

as Palindromes.

The RE makes 2 cuts one in each sequence, in a specific sequence

3’-OH end & 5’ –P end ( phosphodiester bond).The cuts produces

two kinds of DNA fragments ,namely – blunt end & cohesive

/ sticky ends.

Vectors-

A vector is a DNA molecule that has the ability to replicate in

an appropriate host cell & into which the DNA fragment to

be cloned is integrated for cloning.

PROPERTIES –

It should be able to replicate autonomously

It should be ideally less than 10 kb in size

Easy to isolate , purify, & introduced into the hostcell.

Have suitable marker genes.

2 types of Plasmids are found in Agrobacterium sp.-