Genetics and evolution ppt

genetic programming ppt an genetic recombination ppt and ppt on genetic engineering
sarika Profile Pic
Published Date:09-03-2017
Your Website URL(Optional)
GENETICSWhat is Genetics?  It is the science that deals with the study of heredity and variation.  GENETICS came from the word gen, genetikos meaning generative and genesis meaning beginning. Heredity is a biological process where a parent passes certain genes onto their children or offspring.GENE ◉ Biological unit of heredity. ◉ Gene hold the information to build and maintain their cells and pass genetic traits to off springs. ◉ In cells, a gene is portion of DNA.Continued... Gene (DNA) RNA Formation Protein Formation Cell Structure Cell Enzymes Cell FunctionALLELE ◉ Is one member of a pair or series of different forms of a gene. ◉ Homozygous-an organism in which 2 copies of genes are identical i.e. have same alleles ◉ Heterozygous-an organism which has different alleles of the geneChromosomes ◉ Chromatin: DNA, RNA & proteins that make up chromosome ◉ Chromatids: One of the two identical parts of the chromosome. ◉ Centromere: The point where two chromatids attach ◉ 46 chromosomes, 22 pairs Autosomes and 1 pair Sex chromosomes.NUCLEOTIDE: group of molecules that when linked together, form the building blocks of DNA and RNA; composed of phosphate group, the bases: adenosine, cytosine, guanine and thymine and a pentose sugar. In case of RNA, thymine base is replaced by uracil. CODON: series of three adjacent bases in one polynucleotide chain of a DNA or RNA molecule which codes for a specific amino acid. GENETIC CODE: the sequence of nucleotides in a DNA or RNA molecule that determines the amino acid sequence in the synthesis of proteinsCauses of diseases • Accidents • Infections • Genetic diseases • Complex traitsGenetic diseases “ ◉ Inherited diseases ◉ Diseases due to mutations in somatic cells- cancerMutationsDefinition: Permanent changes in the DNA. Those that affect germ cells are transmitted to the progeny. Mutations in the somatic cells are not transferred to the progeny but are important in the causation of cancer and some congenital diseases.CAUSES OF MUTATIONS ◉ Chemicals  Nitrous acid Alkylating agents 5- bromouracil Antiviral drug iododeoxy uridine Benzpyrene in tobacco smoke ◉ X – rays & ultraviolet light ◉ Certain viruses such as bacterial virusTypes of MutationsPoint Mutation These affect a single amino acid or short sequence. These are also called single-base substitutions. • Missense mutations may change the code for a particular protein. • Nonsense mutations may make a change so that the whole chain stops. This mutation codes for a Stop codon.Frame shift Mutations Insertion or deletion of one or two base pairs alters the reading frame of the DNA strand.Snips or SNPs (Single nucleotide polymorphisms) These are the most common type of genetic variation among people. Each SNP represents a difference in a single DNA base for example nucleotide cytosine (C) replaced with the nucleotide thymine (T) in a certain stretch of DNA.Trinucleotide Repeat Mutations Set of genetic disorder caused by trinucleotide repeat in certain genes exceeding normal, stable threshold e.g. Fragile X Syndrome.Classification Of Genetic Diseases ◉ Single Gene Defects/Mendelian Disorders. ◉ Disorders with Multifactorial or Polygenic inheritance. ◉ Cytogenetic Disorders. ◉ Disorders showing atypical patterns of inheritance.Mendelian Disorders A genetic disease caused by a single mutation in the structure of DNA, which causes a single basic defect with pathologic consequencesPatterns Of Inheritance ◉ Autosomal Dominant. ◉ Autosomal Recessive. ◉ X-Linked