ELEMENTARY GENETICS

Dr.P.T.Shukla .

Ph.D. (Genetics)

Retired Head, Botany Division,

Anand Agricultural University,

Anand (Gujarat)

388110.

India.

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All About The Book

There are several books available in the market on the topic Genetics. Most of these books deal with Principals of Genetics in great details. The language used is also very difficult to understand by the students who have very limited knowledge of English language. This comes in their way to understand and grasp the elements of basic Genetics. I had this experience during my teaching to under graduate and post graduate students. Due to semester system , the students have several subjects and this make their study of any subject difficult. The students do not grasp the basic of the subject and mostly memories the brief notes given by the teacher in the class. They do not develop much interest in the subject. Retention of the knowledge in the memory of such students is virtually nil.

If the chapters are written in simple language, properly illustrated with figures the grasping power is improved and the students start developing interest in the topic. The scientific subject involves work of several scientists. The students do not know much about the scientists involved in developing basic concepts. This book gives information on the well known scientists with photographs and their contribution in the field of their specialization. This book is written in simple English , easy to understand by the non English speaking students. Each chapter gives basic information on the topic and deals with the basic concepts in such a way that without much efforts the students can grasp it. Each chapter includes enough information on the subject and covers all the necessary details required to understand the topic. If the students read it carefully, they will be able to grasp all the essentials of Genetics. The e book is available on www.bookganga.com

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CHAPTER 1 : MENDEL’S LAWS OF INHERITANCE

• This chapter deals with Mendel’s Laws of Inheritance in depth. The important terms used in inheritance studies are introduced. Mendel's approach to character inheritance , bracket method of gamete formation for monohybrid, dihybrid and trihybrid crosses is elaborated. Concept of Punnett Square for monohybrid, dihybrid, and trihybrid is discussed. The laws of segregation and independent assortment are explained with suitable examples. Test cross and it’s significance in plant breeding is smphasized. Modification of monohybrid ratio due to incomplete dominance, co dominance and lethal genes is explained with suitable figures.

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CHAPTER 2: CHROMOSOMES AND CELL DIVISION

• This chapter contains information on chromosomes and cell division. The structure of nucleus and chromosomes is dealt with suitable figures. The chromosome morphology with packing of DNA in it is explained. Special chromosomes like Salivary Gland chromosomes, Lamp Brush chromosomes and supernumerary chromosomes are represented by suitable figures and their role is explained. The importance of mitosis and meiosis is explained along with appropriate figures and their significance in inheritance is listed.

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CHAPTER 3: SEX DETERMINATION SYSTEMS

• History of Sex determination is discussed in this chapter along with all the sex determination systems in the plant and animal kingdom such as :

• XX- XY: Mostly found in insects, Human , and in some angiosperms.

• XX-XO: grasshoppers, cockroaches. Nematodes.• ZZ-ZW : birds, fish, reptiles.• Haplodiploidy: Honey bees, Wasps, and Ants.• Non genetic: Effect of temperature and social behavior

on sex expression in fish, reptiles, turtles and alligator.• Sex determination in angiosperms.

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CHAPTER 4 : POLYPLOIDY (A)

• Polyploidy in plants and animals is discussed in this chapter. The major aspects covered are :

• CLASSIFICATION OF AUTOPOLYPLOIDS.

• CHARACTERISTICS OF AUTOPOLYPLOIDS (Plants).

• ORIGIN OF AUTOPOLYPLOIDS IN PLANTS.

• Origin of Allopolyploids.

• ORIGIN OF HEXAPLOID WHEAT.

• PRODUCTION OF ARTIFICIAL SPECIES OF RAPHANOBRASSICA. Contd (B )

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CHAPTER 4 : POLYPLOIDY (B)

• PRODUCTION OF SYNTHETIC WHEAT RYE HYBRID: TRITICALE.

• ORIGIN OF ALLOTETRAPLOID TOBACCO.

• ALLOPOLYPLOIDY IN BRASSICA.

• ALLOPOLYPLOIDY IN COTTON.

• Allopolyploidy in animals.

• ANEUPLOIDY.

• IMPORTANCE OF ANEUPLOIDY AND ALLOPLOIDY.

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CHAPTER 5 : MUTATIONS (A)

• All the important aspects of physical and chemical mutations are covered. The important points covered are:

• History of mutagenesis.

• PHYSICAL MUTAGENS.

• CHEMICAL MUTAGENS.

• BIOLOGICAL AGENTS.

• GENETIC EFFECTS OF RADITIONS. contd (B).

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CHAPTER 5 : MUTATIONS (B)

• UV RADIATION.

• CHEMICAL MUTAGENS : BASE SUBSTITUTION , ALKYLATION , TAUTOMERISM, DEAMINATION,APURINIC GAP, INTERCALATION, BASE ANALOGUES , List of Chemical Mutagens.

• TYPES OF MUTATIONS: POINT MUTATIONS OR FORWARD MUTATIONS , FRAME SHIFT MUTATIONS, MIS SENSE MUTATIONS. Contd (C)

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CHAPTER 5 : MUTATION (C )

• NONSENSE MUTATIONS.• Silent mutations. • CHROMOSOMAL MUTATIONS.• EFFECTS OF MUTATONS.• MUTATION FREQUENCY.• DNA REPAIR SYSTEMS : Photo reactivation

Repair, Recombinational repair, Base excision repair, Mismatch Repair, Adaptive or inducible repair, SOS or inducible error prone repair.

Contd (D)

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Chapter : 5 MUTATIONS (D )

• MUTAGENECITY TESTS IN Drosophilamelanogaster : About Fruit fly , ATTACHED X TECHNIQUE FOR SCORING SEX LINKED VISIBLE MUTATIONS, MULLER 5 TECHNIQUE .

• MUTATION INDUCTION IN CROP PLANTS :MUTAGENIC TREATMENT, STEPS FOR ISOLAION OF MUTANTS .

• SIGNIFICANCE OF MUTATIONS, APPLICATION OF MUTATIONS, MUTATIONS AND CROP IMPROVEMENT.

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CHAPTER 6 : GENE INTERACTIONS

• The history of gene interaction is elaborated in this chapter. The allelic and non allelic interactions are described. The following types of gene interactions in plants and animals are discussed with figures :

• COMPLEMENTARY GENE INTERACTION.• SUPPLEMENTARY OR RECESSIVE GENE INTERACTION.• DOMINANT EPISTASIS.• DUPLICATE FACTOR.• INHIBITARY FACTOR.• POLYMERIC OR ADDITIVE GENE INTERACTION.• PARTIAL DOMINANCE AT INHIBITORY LOCUS.• INCOMPLETE DOMINANCE AT TWO ADDITIVE LOCI.• DOMINANT MODIFICATION OF DUPLICATE GENES.

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CHAPTER 7 : LINKAGE AND CHROMOSOME MAPPING

• History of linkage and chromosome mapping.

• COUPLING AND REPULSION PHASE.

• COUPLING OR CIS ARRANGEMENT.

• REPULION OR TRANS ARRANGEMENT.

• THREE POINT TEST CROSS.

• INTERFERENCE AND COINCIDENCE.

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CHAPTER 8 : CYTOPLASMIC INHERITANCE

• Cytoplasmic Inheritance in Mirabelis jalapa

• PIGMENTATION IN FLOUR MOTH (Ephestiakuhniella).

• COILING OF SHELL IN SNAIL (Limnaea peregra).

• CYTOPLASMIC INHERITANCE IN MICE.

• CYTOPLASMIC MALE STERILITY.

• EXTRA CHROMOSOMAL PARTICLES :

KAPPA PARTICLES IN PARAMECIUM.

SIGMA PARTICLES IN DROSOPHILA.

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Chapter 9 : DNA STRUCTURE AND FUNCTION

• TRANSFORMATION EXPERIMENTS OF GRIFFITH .• Experiment of Avery, MacLeod and McCarty in 1944.• Waring Blender Experiment of Hershey and Chase, 1952.• WATSON CRICK PROPOSED DNA STRUCTURE, 1953.• STRUCTURE OF DNA.• DNA REPLICATION.• GENETIC CODE (THE LANGUAGE OF LIFE).• PROPERTIES OF GENETIC CODE.• CENTRAL DOGMA : DNA RNA Protein.• MESSENGER RNA (mRNA) , RIBOSOMAL RNA (r RNA),

TRANSFER RNA (tRNA).• PROTEIN SYNTHESIS.

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CHAPTER 10 :GENE STRUCTURE AND FUNCTION

• Historical aspects of gene structure and function.

• Gene splicing in eukaryotes .

• TYPES OF OPERONS.

• REGULATION OF LAC OPERON IN E.COLI.

• TRYPTOPHAN OPERON.

• GENE CONTROL IN EUKARYOTS.

• TRANSLATIONAL CONTROL (PROTEIN SPLICING).

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