Definition of genetics , history, premendelian genetics, post Mendeliangenetics, classical genetics and cytogenetic s related

1. WELCOME
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2. Dr. Balasaheb Sawant Konkan Krishi
Vidhyapeth
COLLEGE OF AGRICULTURE
2017-18
PRINCIPLES OF GENETICS
COURSE INSTRUCTOR:
Dr . Devmore,
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3. Introduction of genetics :
important landmarks in genetics
and important concepts in
genetics.
By :
K. SUDHA MANI
ADPM/17/2555
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4. GENERAL OBSERVATIONS
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5. PRE MENDELIAN CONCEPTS ABOUT
HEREDITY
• Theory of spontaneous generation.
• Preformation theory.
• Theory of Epigenesis.
• Theory of Acquired characters.
• Theory of Pangenes.
• Germplasm theory.
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6. Important definitions to remember
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7. REPRODUCTION IN PLANTS & ANIMALS
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8. Sudha's KSM 95

9. Mendelian Genetics
• Dominant traits - traits that are expressed.
• Recessive traits - traits that are covered up.
• Alleles - the different forms of a characteristic.
• Punnett Squares - show how crosses are made.
• Probability - the chances/ percentages that
something will occur.
• Genotype - the types of genes (Alleles) present.
• Phenotype - what it looks like.
• Homozygous - two of the same alleles.
• Heterozygous - two different alleles
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10. Punnett square example
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11. LAWS OF MENDEL
• LAW OF DOMINANCE
• LAW OF SEGREGATION
• LAW OF INDEPENDENT ASSORTMENT
1865 – Paper on Experiments in plant hybridization
to the Brunn society.
 1900 – Rediscovery of mendel papers.
1901 – Pearson – chi square test.
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12. • LAW OF DOMINANCE: in hybrid expression of a
allele completely over other.
• LAW OF SEGREGATION: When a pair of alleles
is brought togeather in a hybrid they segregate
in to gametes during the formation of gametes.
• LAW OF INDEPENDENT ASSORTMENT: The
factors in an allelomorphic pair separate
independently to the separation of factors in
another allelomorphic pair.
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13. DEVIATION FROM MENDEL LAWS
• 1906 – Bateson and Punnet – linkage in sweet
peas.
• 1906 – Neselson and Ehle – multiple factor
hypothesis.
• - Landsteiner –
human ABO blood
groups.
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14. • Paramutations.
• Incomplete dominance.
• Pletropism.
• Polyploidy.
• Modifications of F2 rations.
• Multiple alleles.
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15. DISCOVERY OF CELL
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16. NUCLEUS AND CHROMOSOME
• 1831- Robert Brown discovered nuclei in cells.
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17. • 1871 – Meischer – isolated nucleic acids and
called it as nuclein.
• 1875 – Strausberger describes cell division in
plants.
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18. • 1881 – Balbani – discovered giant
chromosomes in salivary gland chromosomes.
• 1882 – Flemming – discovered lamp brush
chromosomes, coined mitosis.
• 1888 – Waldeyer – coined the term
chromosome.
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19. • 1902 – Mc Clung – discovered accessory
chromosome.
• 1913 – Sturtevant first genetic map.
• 1920 – Blakeslee trisomics in Datura.
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20. CYTOGENETICS
• 1830 – Amici – pollen tube grows into style
and ovule.
• 1875 – Hertwig fertilization involves fusion of
egg and sperm nuclei.
• 1902 - Sutton & Boveri – proposed
chromosome theory of heredity.
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21. 1931 – Stern – cytological proof of
crossing over.
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22. CLASSICAL GENETICS
• 1903 – Johannsen coined the term gene,
genotype, phenotype.
• 1905 – Bateson – term genetics.
H. de Vries – mutation theory.
• 1927 – Muller – mutation induction by X-rays in
Drosophila.
• 1928 – Stadler – mutation
induction by X-rays in Maize.
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23. • 1914 – Bridges nondisjunction of X
chromosomes in Drosophila
• 1925 – Bridges genic balance theory of sex
determination.
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24. BIOCHEMICAL GENETICS
• 1909 – Garrod published book on inborn errors of
metabolism.
• 1941 – Beadle and tatum – one gene one enzyme
theory.
• 1952 – Zinder and Lederberg trasduction in
salmonella.
• 1925 – Goodspeed – 1st synthetic amphidiploid in
Nicotiana.
• 1933 – Rhoades – cytoplasmic male sterility in
maize.
• 1937 – Blakeslee and Avery – chromosomal
doubling effect of colchicine.
• 1938 – Mc clintock Bridge-breakage-fusion-bridge
cycle. Sudha's KSM 95

25. MOLECULAR GENETICS
• 1944 - Avery, Macleod, Mc Cratey – DNA is
transforming principle.
• 1950 – Mc Clintock Ac Ds system in maize.
• Hershey and chase – DNA is genetic material in
E.coli.
• 1955 – Benzer – rII locus of T4 phage of E.coli
coins terms cistron, recon, and muton.
• 1956 – Kornberg co. invitro synthesis of DNA &
genetic code.
Ochoa – invitro synthesis of RNA.
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26. 1953 – Watson and Crick – proposed
double helix model of DNA.
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27. 1958 – Meselson and stahl –
semiconservative replication of DNA.
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28. • 1959 – Whittaker – classification of organisms.
• 1961 – Jacob & Monod – operon concept of
gene.
• 1968 – Gilbert and Dressler – Rolling circle
model of DNA.
• 1970 – Baltimore and temin – reverse
transcriptase in two oncogenic RNA viruses.
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29. Central Dogma of Biology
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30. RECOMBINANT DNA TECHNOLOGY
• To obtain a large no. of copies of a DNA
sequences/segments.
• To recover large quantities of the protein
encoded by the cloned DNA sequence.
• To integrate the DNA sequence into the
genome of the target organism (transgenic
organisms).
• 1907 – E.F.Smith – Agrobacterium tumefaciens
causes crown gall diseases.
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31. Sudha's KSM 95

32. • 1997 - I. Wilmut Cloned sheep – Dolly.
• 1997 - Prusiner Studied prions – Mad cow disease.
• 1998 - Delta & Pine Co. Developed the terminator gene
technology.
• 1998 - Monsanto Co. Developed bollguard variety of
cotton.
• 1998 - T. Wakayama and R. Yanagimachi - Created the
first cloned mice.
• 2000 - Roslin Institute Created the first cloned pigs.
• 2001 Advanced Cell Technology Birth of first cloned
Asian ox called “Gaur”.
• 2002 Natl. Institute of Agronomic Research, France.
• Created the first cloned rabbit
• 2002 Texas A & M Univ. U.S.A.- Created the first cloned
cat called “Cc
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33. Sudha's KSM 95