by hafiz m Waseem university of education Lahore

2. MODERN GENETICS
HAFIZ M WASEEM UNIVERSITY
OF EDUCATION LAHORE

3. Context
 Introduction
 Definition
 Structure of DNA
 Central dogma
 DNA replication
 Transcription
 Translation
 Mutation
 Genegic engineering
 Medical Genetics research

4. MODERN GENETICS
 What Is Genetics?
 The study of gene ,heredity,variation ,and mchanism of heredity from
one generation to next generation.
 Inheritance
 Classicla Genetics
Based on visible results of reproductive acts.
 It is basically the mendlian Genetics
 Modern Genetics
 .The modern genetics is the study of DNA and how it serves as the
molecular basis of heredity.

5. MODERN GENETICS
DEFINITION
“That body of Method and analysis that percieve genetics
as the study of economy of nucleic acid and associated compound.”
Modern genetics focuses on the chemical substance
that genes are made of, called deoxyribonucleic acid, or DNA, and
the ways in which it affects the chemical reactions that constitute
the living processes within the cell.

6. MODERN GENETICS
 Why Mendle is clled the father of modern gendtics ?
 Modern genetics began with the work of the
 Augustinian friar Gregor Johann Mendel.
 His work on pea plants, published in 1866,
 established the theory of Mendlian inheritance.
 Mendel work suggested that heredity was not acquired .
 He proposed that “Each trait is control by particles he called them
 unit factor Now it is known as gene.
 But the importance of Mendel’s work does not gain understanding until 1900 after his death

7. Modern Genetics
 .The modern genetics is the study of DNA and how it serves as the molecular basis of
heredity begans 1920s it became clear that chromosome contained gene for genetics
trait. A number of experiment were important in establishing that DNA was the genetic
material of living organisms.
 Mendel “unit of inhertance”
 Gene
 Chromosome
 Nucliec Acid

8. Modern Genetics
 A number of experiment were important in establishing DNA was indeed the genetic
material of living orgnism
 _Griffith Experiment(1928)
 _ Harshey and chase experiment (1952)
 _Griffith Experiment(1928)
 Griffith was studying two strain of bacteria streptococcus pneumoniae which cause
pneumonia and other factor infection
1. smooth strain (s)
2. Rough strain (R):

9. Griffith Experiment
Griffith concluded that the genetic instruction had been transferred to
rough bacteria from dead smooth bacteria . He called this the process of
Transformation

10. _Harshey and chase experiment (1952)
 They proofed that DNA Rather than protein carry the heredity information of life
EcoliBactaria : Bactariophage is a virus that infect bactaria only contain a protein coat
capsid and DNA carried the genetic instruction to make more viruses
 protein capsid : labelled with Radioactive Sulphur s35
_DNA : labelled with radioactive phosphorus p38
Bacterial cells that are infected with the two types Bactariophage and examine
labeled viral protein did not enter into infected bactaria
While labeled viral DNA did enter into infected Bactaria so it is concluded that,
DNA Is the molecule that carries the genetic information to make new viruses

11. Nucleic Acid
 DNA(Heredity material)
 DNA was discovered in 1869 by Swiss researcher Friedrich
Miescher
 The three-dimensional structure of DNA, first proposed by James D.
Watson and Francis H. C. Crick in 1953, consists of two long helical
strands that are coiled around a common axis to form a double helix
 DNA Nucloetide

12. Nucleic Acid
 RNA
 Ribonucleic acid is a polymeric molecule essential in various biological roles in coding, decoding,
regulation and expression of genes
 Types of RNA
 There are three types of RNA: mRNA, tRNA, and rRNA. mRNA is the intermediary between the
nucleus, where the DNA lives, and the cytoplasm, where proteins are made. rRNA and tRNA are
involved in protein synthesis. Additional RNAs are involved in gene regulation and mRNA
degradation.

13. Central Dogma
 DNA Replication
 The first step of central dogma is DNA replication
 It is a process in which DNA produce its copy in which one strand is new and other is old as
it conserved in new molecule and thus DNA replication is said to be semiconservative.

14. Central dogma
 Transcription: Transfer of the genetic message from DNA to mRNA .
The genetic information are not translated directly into protein but
first is transcribed into messenger RNA Transcription involve
numerous enzyme that unwind a region of a DNA molecule ,initiate
and mRNA synthesize and modify the mRNA after transcription is
complete . Unlike DNA only one or few genes are exposed and only
one of two DNA strand s transcribe. DNA unwind and RNA is made by
reading the DNA template. DNA serves as a template for the synthesis
of mRNA from RNA nucleotides in the nucleus.

15. Central dogma
 The process of protein formation from mRNA is called translation
 mRNA molecules carrying a specific code determined by the base sequence of the DNA
template move from the nucleus to the cytoplasm. Strands of mRNA carrying codons
transcribed from DNA, move the ribosomes in the cytoplasm.
 Codon: a triplet in a DNA molecule .
 Triplet: grouping of three nitrogenous bases in DNA or RNA molecules
Different triplets of nitrogenous bases in tRNA molecules pick up specific amino
acids in the cytoplasm and carry them to mRNA at the ribosomes Amino acids
are put into position on the ribosome with instructions from the triplet codes of
tRNA and mRNA. With the aid of enzymes and ATP (energy), the amino acids are
bonded to form a polypeptide chain (protein) on the ribosom

17. Mutation
 A mutation is a change in a DNA sequence. Mutations can result from DNA
copying mistakes made during cell division, exposure to ionizing radiation,
exposure to chemicals called mutagens, or infection by viruses. Germ line
mutations occur in the eggs and sperm and can be passed on to offspring, while
somatic mutations occur in body cells and are not passed on.

18. Type of Mutation
• Micro mutations :it is also called point mutation
• Macro mutations
• Numerical Aberration
1. Aneuploidy
2. Euploidy
• Structural Aberration
1. Deletion
2. Duplication
3. Inversion
4. Insertion
5. Translication

19. Genetic engineering
 The group of applied techniques of genetics and biotechnology used to cut up and join together
genetic material and especially DNA from one or more species of ocharacteristics
 Cultivating plant and breeding domestic animals
1. Selective breeding
2. Gene manuplation
3. Cloning
4. Recombinent DNA

20. Recombinent DNA
 Recombinant DNA, molecules of DNA from two differen species that are
inserted into a host organism to produce new genetic combinations that are of
value to science, medicine, agriculture, and industry.
 Steps
 Isolation of the Gene of Interest (DNA Sequence) - Gene Therapy.
 Insertion of the Isolated Gene into a Vector.
 Selection of Transformed Host Cells.
 Expression of the Gene introduced into the host.

21. Medical Genetic Research
 Screening:Analysis of body fluid
 Genetic counseling
 Karyotyping
 Gene therapy
 Gene therapy is an experimental technique
that uses genes to treat or prevent disease.

22. References
 Griffiths AJ, Miller JH, Suzuki DT, Lewontin RC, Gelbart, eds. (2000). "Genetics and the
Organism: Introduction". An Introduction to Genetic Analysis (7th ed.). New York: W.H.
Freeman. ISBN 978-0-7167-3520-5.
 ^ Hartl D, Jones E (2005)
 ^ "the definition of genetics". www.dictionary.com. Retrieved 25 October 2018.
 ^ "Genetikos (γενετ-ικός)". Henry George Liddell, Robert Scott, A Greek-English Lexicon.
Perseus Digital Library, Tufts University. Archived from the original on 15 June
2010. Griffiths AJ, Miller JH, Suzuki DT, Lewontin RC, Gelbart,