Mutation:
(i) Mutation is defined as the sudden heritable change in the nucleotide sequence of DNA in an organism.
(ii) It is a Process by which genetic variations are created which in turn brings about changes in the organism.
(iii) The organism which undergoes mutation is called a mutant.
(iv) The factors which induce mutations are known as mutagens or mutagenic agents.
(v) Mutagens are two types namely physical mutagens and chemical mutagens.
(i) Physical mutagens:
Radiations like X-rays, α, β and γ-rays, UV rays, temperature, etc. which induce mutations are called physical mutagens.
(ii) Chemical mutagens:
(i) Chemical substances that induce mutations are called chemical mutagens.
(ii) Eg: Mustard gas and nitrous acid. The utilization of induced mutation in crop improvement is called mutation breeding. Achievements of mutation breeding:
Achievements of mutation breeding:
(i) Sharbati Sonora wheat produced from Sonora-64 by using gamma rays.
(ii) Atomica 2 rice with saline tolerance and pest resistance.
(iii) Groundnuts with thick shells.

Polyploldys are characterised by gigantism
An organism having more than two sets of chromosomes is called polyploid. It causes increase in size. Polys = Many + aploos = One fold + eidos = Form (E.g) Watermelon

Reason:
(i) No chemicals fertilisers are used on the soil.
(ii) No pesticides are sprayed on the plants.
(iii) The seeds used to produce plants have not been genetically altered.

(i) Genetic engineering is the manipulation and transfer of genes from one organism to another organisms to create a new DNA called as recombinant DNA(rDNA).
(ii) The term recombinant is used because DNA from two different sources can be joined together. Hence, genetic engineering is also called as recombinant DNA technology.

(i) Animal breeding aims at improving the genotypes of domesticated animals to increase their yield and improve the desirable qualities to produce milk, egg and meat.
(ii) When breeding takes place between animals of the same breed, it is called inbreeding. The cross between different breeds is called out breeding.

(i) Genetic engineering is the manipulation and transfer of genes from one organism to another organism to create a new DNA called as recombinant. DNA (rDNA).

Continued inbreeding reduces fertility and productivity. Inbreeding exposes harmful recessive genes that are eliminated by selection.

He can adopt clonal selection since banana reproduces asexually from the underground stem.

Plant materials brought into a country must be free from pathogens. It may lead to outbreak of new disease or introduction of a new pathogen into the environment. Thus plant materials (seeds / saplings) are tested in plant quarantine.

(i) The human genome has 3 billion base pairs. Each person's DNA sequence is unique due to the small difference in the base pairs.
(ii) DNA finger printing is the easier & quicker method to compare the genetic difference among the two individuals. This technique was developed by Alec Jeffrey.
(iii) The technique analyses each individual's unique DNA sequences and provides distinctive characteristics of individual which helps in identification.
(iv) Variable Number of Tandem Repeat sequences (VNTRs) serve as molecular markers for identification.
(v) In human beings, 99% of the DNA base sequences are the same and this is called as bulk genomic DNA.
(vi) The remaining 1% DNA sequence differs from one individual to another. and is present as small stretch of repeated sequences which is known as satellite DNA.
(vii) The number of copies of the repeat sequence also called as VNTRs differs from one individual to another, and results in variation in the size of the DNA segment.
(viii) Satellite DNA bring about variation within the population. Variation in DNA banding pattern reveals differences among the individuals.
Applications of DNA Fingerprinting:
(ix) DNA fingerprinting technique is widely used in forensic applications like crime investigation such as identifying the culprit. It is also used for paternity testing in case of disputes.
(x) It also helps in the study of genetic diversity

(i) Sexually reproducing organisms have two complete set of chromosomes in their somatic cells. This is called diploid (2n).
(ii) The gametic cells have only one set of chromosome. This is called haploid (n).
(iii)  An organism having more than two sets of chromosomes is called polyploid. Such condition is called Polyploidy.
(iv) It can be induced by physical agents such as heat or cold treatments, X-rays, Chemical agents like colchicine.
Achievements of polyploidy breeding:
(i) Seedless watermelons (3n) and bananas (3n).
(ii) TV-29 (triploid variety of tea) with larger shoots and drought tolerance
(iii) Triticale (6n) is a hybrid of wheat and rye. To make this plant fertile polyploidy is induced. It has higher dietary fibre and protein.
(iv) Raphano brassica is a allotetraploid by colchicine treatment.