Genes are segments of DNA that contain codes for specific proteins. Genes are located on chromosomes and are passed down from parents to offspring, determining traits. DNA has a double helix structure, with nucleotides containing bases of adenine, guanine, cytosine and thymine bonded together. Chromosomes, composed of DNA and proteins, contain genes and occur in pairs in somatic cells. Karyotyping identifies the number, size and structure of chromosomes to detect any abnormalities.

1. BASIC CONCEPT OF GENE ,
DNA,& CHROMOSOME
INTRODUCTION
HISTORY OF GENETICS
IMPORTANT TERMS OF GENETICS
BASIC CONCEPT OF GENE
STRUCTURE OF DNA
CONCEPT OF CHROMOSOME

2. INTRODUCTION
Genetics is the study of genes & tries to
explain what they are & how they work .
Genes are how living organism inherit
features or traits from their ancestor .
Children usually look like their parents
because they have inherited their parents
gene . Genetics also explain how this traits
are passed from generation to generation.

3. HISTORY OF GENETICS
Father of genetics- Gregor johann mendel
1869-Friedrich Miescher identified the DNA
1900-1913-
Chromosomal theory of inheritance-Sutton
& Boveri
Genes on chromosome- TH Morgan
Genes linearly arranged on chromosome-
AH startevant.

4. HISTORY OF GENETICS
1941-George Beadle & Ed
tatum r/t enzyme &
biochemical process.
1944-DNA is a genetic material
,by Oswald Avery.

5. TERMS R/T GENETICS
 GENETICS-The science that deals with the
study of heredity,& variations is known as
genetics.
 CYTO GENETICS-The field deal with
structure of nucleus of cell & its parts(
chromosome) normal & abnormal
chromosome can be studied.
 MOLECULAR GENETICS-The field deal with
the molecular structure & function of genetic
material .( gene & DNA)

6. TERMS R/T GENETICS
 BIOCHEMICAL GENETICS : Field deal with
the biochemistry of genetic material for
normal metabolic process.
 HEREDITY :Transmission of characteristics
from parent to offspring.
 TRAIT:Is a distingushing quality or
characteristics typically belonging to a person
or genetically determined characteristics.
 GENOTYPE:Is a set of gene on DNA
responsible for unique trait & characteristics.

7. TERMS R/T GENETICS
 PHENOTYPE: Is the physical appearance or
characteristics of an organism.(environment,
humidity, stress)
 ALLELE :Each alternative for a gene,occurs in
pairs.
 HETEROZYGOUS:Two different allele.
 HOMOZYGOUS: Same allele.
 DOMINANT TRAIT:Characteristics when
present is always expressed.

8. TERMS R/T GENETICS
RECESSIVETRAITS : Masked by dominant traits
. Only appear in case of homozygous allele.

9. BASIC CONCEPT OF GENE
GENE-Basic physical & structural unit of
hereditysequence of neucleotides in DNA that
help in protein synthesis.
CHARACTERISTICS:
1. Individual factor that don’t blend with one
another.
2. Control characteristics of living things
3. Determine the nature & function of the cell.
4. Responsible for development & structure of
human body.

10. BASIC CONCEPT OF GENE
CHARACTERISTICS:
5.GENOME- Full set of gene in each cell of an
organism.
Human genes are reffered to as human genome
( 120000)
6.Some of the genes are dominent (produce
traits in every generation).Somes are
recessive(produce traits in several
generation).

11. BASIC CONCEPT OF GENE
CHARACTERISTICS:
7. Genes don’t act alone influenced by external
& internal environment.
8. In somatic cell has about 30,000 genes in the
nucleus.there are some non nuclear gene,
present in mitochondria & cytoplasm.
9. For each gene each individual receive an
allele from each parent.

12. CONCEPT OF DNA
DNA, or deoxyribonucleic acid, is the
hereditary material in humans and almost all
other organisms. Nearly every cell in a
person’s body has the same DNA. Most DNA
is located in the cell nucleus (where it is called
nuclear DNA), but a small amount of DNA
can also be found in the mitochondria (where
it is called mitochondrial DNA or mtDNA).
LOOKS LIKE ATWISTED LADDER.

13. CONCEPT OF DNA
STRUCTURE:
NUCLEOSIDE-N2 Base + Sugar
NUCLEOTIDE-N2Base+Sugar+Phosphate
N2 Base-They are two types
1. Purine-adenine(A),guanin(G)
2. Pyrimidine-cytocin(C),thymin(T),uracil(U)
Pentose sugar-
1. Ribose sugar
2. Deoxyribose sugar

14. CONCEPT OF DNA
Phosphate group
Nucleotide chain-more
nucleotide chain is called poly
nucleotide chain.

16. DNA STRUCTURE
WATSON & CRICK DNA MODEL-
 Made up of two neucleotide chain .Backbone
is made up of sugar & phosphate.Bases are
projected inside & backbone is projected
outside.
 Two chain have antiparallal polarity
 Ratio between A&T ,G&C are constant equal.
A+G=T+C

17. DNA STRUCTURE
 Distance between two N2 base-
3.4 armstrong.
 There are 10 base in one complete
turn.
 One polypeptide chain width is 10
armstrong.

20. CONCEPT OF CHROMOSOME
A threat like structure that is visible during cell
division.Described by E Strasburger.
1.Before replication 1 chromosome with 1
chromatid.
2.After replication 1 chromosome with two
chromatid.
3. Homologus chromosome in somatic cell.
2n=46
4.Haploid chromosome in gamets.n=23

21. CONCEPT OF CHROMOSOME
STRUCTURE:

22. CONCEPT OF CHROMOSOME
CHEMICAL COMPOSITION:
DNA-40%
PROTEIN-60%( Histone & non histone)
NEUCLEOSOME-8molecule of histone
octamere+147 bp DNA
More neucleosome form chromatin and its form
chromosome.

23. CONCEPT OF CHROMOSOME
 KARYOTYPING-Is test to identify & evaluate
the size, shape,& no. of chromosome in a
sample of body cells.
 KARYOTYPE-Is a standard arrangement of a
photographed or imaged stained in which
chromosome pairs are arranged in order of
decreasing length.

24. CONCEPT OF CHROMOSOME
PROCESS-
 Most commonly used cells are fibroblasts of
skin,bone marrow cell, peripheral blood
lymphocyte,amniotic fluid cell from a
pregnant women,viable cell can also be
obtained within few hours of death.
 From peripheral blood the lymphocytes are
separated.
 Added to a culture medium with
phytohemagglutinin added to it.

25. CONCEPT OF CHROMOSOME
 The cells are cultured under aseptic measure
at 37 degree celcius for about 3 days.
 Adding a small amount of cholchicine
 After one hour of adding cholchicine ,a
hypnotic solution is addedto swell the cells,&
allow the chromosomes to spread on the
slide.
 Chromosomes are arranged in decreasing
order from 1-22& two sex chromosome.

26. CONCLUSION
Genes are segment of de oxyribonuclic acid that
contain the code for a specific protein.That
function in one or more types of cell;ls in the
body.

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