Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
List of types of proteins wikipedia , lookup
Silencer (genetics) wikipedia , lookup
Gene regulatory network wikipedia , lookup
Deoxyribozyme wikipedia , lookup
E. coli long-term evolution experiment wikipedia , lookup
Genome evolution wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
History of molecular evolution wikipedia , lookup
Genetic engineering wikipedia , lookup
EVOLUTION WHERE, WHEN & HOW DID HUMAN RACE ARISE? EVOLUTION The universe, the stars, the earth and all living things have evolved through a long history that was not fore ordained or programmed. History of continual and gradual change shaped every thing by processes consistent with the laws of physics ORIGINS OF HUMANKIND Discovery of unusual human bones in 1856 in The Neanderthal Valley, Germany. Pronounced bony ridges over the eyes Backward sloping forehead Receding chin Unusually prominent teeth Brain larger than our HUMAN KIND Humans are creatures whose roots lie in the animal. They are described as animals who make tools, reason, use fire, laugh or many other things. Humans are animals who wonder, intensely and endlessly about their origin. EVIDENCE FOR EVOLUTION THE MISSING LINKS • Fossils are the remnants of ancient plant and animals that has become extinct. • Similar strata contained similar fossils • Lowest strata contained the oldest • Life forms change slowly in the direction of modern life • Discovery of JAVA man by Marie Eugene Dubois in 1891 • Discovery of PEKING man in 1923 • Raymond Arthur Dart found fossils of Australopithecus Africanus TAUNG child in 1924 which was 2.5 million years old • Donald Johnson discovered 3.2 million years old Australopithecus, LUCY in 1974 • Gen Suwa discovered 4.4 million years old A. Aramis in 1994 in Ethiopia. EVOLUTION IS • Recklessly opportunistic. It favors any variation that can provide a complete advantage over the other member of and organism. • There is no programmed control or direction for the progression. THE ORIGINS OF SPECIES 1859 CHARLES DARWIN DARWIN’S PRINCIPLES OF EVOLUTION EVOLUTION VIA NATURAL SELECTION • The world is not static but evolving • The process of evolution is gradual and continuous • Similar organisms are related and decent from a common ancestor • There is a process of Natural Selection which is a two step process. – Variations in generations – Survival of the fittest • Production of genetic variability: A random intrinsic process which proceeds via mutation, recombination and chance events. • Ordering of that variability be selection: An extrinsic ordering which determines the evolutionary direction. ARGUMENTS AGAINST EVOLUTION • If the diversity of species is due to evolution, it should be still going but one cannot see it. • God is perfectly capable of creating life • There should be a guiding intelligence behind evolution • It is not deterministic COUNTER ARGUMENTS FOR BIOLOGICAL EVOLUTION • Evolution goes so slowly that it is not visible to naked eye. • If one argues that it is God s will, than science comes to an end. • Need for a guiding intelligence? QUESTIONS DARWIN COULD NOT ANSWER BIOLOGICAL BASIS FOR EVOLUTION • How do offspring's inherit from parent? • Why do living things vary and how variation occurs? • What rules govern the handing down of traits from one generation to the next? • Heredity is transmitted by a large number of independent, independent units known as genes. • When parents contribute the same kind of gene, a constant characteristic is produced in the children. A hybrid results from two different kinds. • Evolution is the changes in the genetic composition of a population with the passage of each generation. CHROMOSOME Mendel s Experiment on Peas Chromosomes are microscopic bodies found in the nuclei of plants and animals that carry the hereditary materials. They are called genes that determine the growth, development and characteristics of an organism. DEOXYRIBONUCLEIC ACID (DNA) DNA is the genetic substance of all living cells in which the hereditary information is transmitted from each generation to the next by the codes present. These molecules are very long, one dimensional chains, composed of four types of subunits. The genetic information is conveyed in the sequence of the subunits. MUTATION A mutation is the alteration of the genetic code which than results in the wrong amino acid sequences after translations. Mutations may not always be harmful for the organisms. Mutations can be either hereditary or they are acquired. GENE POOL • A gene is the functional unit of DNA. The code written in the genes is translated into aminoacid sequences that constitutes the proteins. All the genes possessed by a population constitutes its gene pool. If there is a random mating within a large population and if there are no mutations, the gene pool within the population will remain constant. Genetic equilibrium will be maintained and no evolution will occur. TYPES OF MUTATIONS • Hereditary mutations. • Acquired mutations • Chromosomal mutations • Mutagens HEREDITARY MUTATIONS • Genes come in pairs (one from each parent). Many genes have in several variant forms known as alleles. Different alleles produce variations in inherited characteristics. The observed trait may be dominant or recessive. If both alleles in a particular gene is same, the individual is said to be homozygous, if different, heterozygous for that trait. In heterozygous case, a dominant allele prevails over a normal allele. ACQUIRED MUTATIONS • They arise within individual cells and accumulate throughout a lifetime. They are generally due to errors that occur during DNA replications and cell divisions. They may also arise by exposure to environmental mutagens such as radiation and toxins. Cells have repair mechanisms, however, they may become less efficient with age or mistakes may accumulate over time. These are passes only to the direct descendants of those cells. CHROMOSOMAL MUTATIONS • These can occur at chromosomal levels during cell division. Especially important for woman having babies at old age. When large regions of chromosome are altered, it may loose the ability to separate during normal cell divisions. This way the new cell may get more or less of its share of DNA. When there are extra or too few copies of the gene, the cell runs into trouble. Down Syndrome is chromosomal abnormality which involves an extra copy of chromosome 21. MUTAGENS Agents that cause mutations such as: • • • • • UV radiation Temperature Toxins (mustard gas, benzopyrenes, aflotoxins) Acrylic dyes Alkylating agents FACTORS ALTERING GENETIC EQUILIBRIUM Y-CHROMOSOME VARIATION IN THE TURKISH POPULATION • Mutation: Inheritable change in the structure of a gene which occurs randomly at a low but constant rate. • Natural Selection: Species that can cope with the environment including climate, competitors and predators will have chance to evolve. • Genetic Drift: Isolated human population may undergo genetic changes as a result of chance rather than natural selection. • Mixing: Mixing of geographically defined populations Y-CHROMASOME HAPLOTYPES OF TURKISH POPULATION REGIONAL VARIATION OF YCHROMOSOME OF TURKISH POPULATION PRINCIPAL COMPONENT ANALYSIS OF YCHROMOSOME VARIATIONS OF WORLD POPULATIONS YCHROMOSOME COMPARISON OF WORLD POPULATIONS STATISTICAL COMPARISON OF YCHROMOSOMES