HISTORY OF THEDEVELOPMENT OF GENETICS AS SCIENCE
GENETICS-a discipline of biology.-the science of genes, heredity, and variation in living organismsand deals with the molecularstructure and function ofgenes, gene behavior in context ofa cell.
HYBRIDIZATION-to produce offspring from two organismsof a different variety, breed or species.-It can be induced naturally, such as thenatural crossbreeding of two differentflower varieties through windpollination, or manipulated throughgenetic implantations by humans. Humanscan manipulate genetics to create hybridsby either placing two different species ofan animal or plant on the same confinementand waiting for them to breed, orimplanting hybridized genes into adeveloping fetus or sex cell.
Gregor Johann Mendel-scientist and Augustinian friar who gained posthumous fame asthe founder of the new science of genetics.-Mendel demonstrated that the inheritance of certain traitsin pea plants follows particular patterns, now referred to as thelaws of Mendelian inheritance.-Gregor Mendel, who is known as the "father of moderngenetics."
Hugo Marie de Vries -Dutch botanist and one of the first geneticists. Heis known chiefly for suggesting the conceptof genes, rediscovering the laws of heredity in the1890s while unaware of Gregor Mendels work, forintroducing the term "mutation", and for developinga mutation theory of evolution.
William Bateson-Englishgeneticist and a Fellow of St.Johns College, Cambridge. He was thefirst person to use the term genetics todescribe the studyof heredity and biologicalinheritance, and the chief populariser ofthe ideas of Gregor Mendel followingtheir rediscovery in 1900 by Hugo deVries and Carl Correns.
Alfred Henry Sturtevant-He was an American geneticistSturtevant constructed the firstgenetic map of a chromosome in 1913.Throughout his career he worked on theorganism Drosophilamelanogaster with Thomas Hunt Morgan.By watching the development of flies inwhich the earliest cell divisionproduced two different genomes, hemeasured the embryonic distance betweenorgans in a unit which is calledthe sturt in his honor. In1967, Sturtevant received the NationalMedal of Science.
Ronald Aylmer Fisher-Fisher was an ardent promoterof eugenics, which also stimulated andguided much of his work in the genetics ofhumans. His book The Genetical Theory ofNatural Selection was started in 1928 andpublished in 1930. It contained a summary ofwhat was already known to the literature. Hedeveloped ideas on sexualselection, mimicry and the evolution ofdominance.
-He famously showed that the probability ofa mutation increasing the fitness of anorganism decreases proportionately with themagnitude of the mutation. He also provedthat larger populations carry morevariation so that they have a larger chanceof survival. He set forth the foundationsof what was to become known as populationgenetics.
Frederick Griffith-was a British bacteriologist whose focuswas the epidemiology and pathology ofbacterial pneumonia.-He showed that Streptococcuspneumoniae, implicated in many casesof lobar pneumonia, could transform fromone strain into a different strain. Theobservation was attributed to anunidentified transformingprinciple or transforming factor. Thiswas later identified as DNA.
1. Behavioral Genetics- examines the role of genetics in animal (including human) be havior.2. Classical Genetics- consists of the technique and methodologies of genetics that predate the advent of molecular biology.3. Conservation Genetics- interdisciplinary science that aims to apply genetic methods to the conservation and restoration of biodiversity.4. Ecological Genetics- study of genetics in natural populations.5. Genomics- discipline in genetics concerning the study of the genomes of organisms.
1. Animal Husbandry- the agricultural practice of breeding and raising livestock.2. Plant Breeding- make use of a plant experiment to know how a trait is passed from generation to generation.3. Multiple-locus testing4. Pedigree Analysis- analysis of themembers of the family.Pictorialrepresentation of the members of thefamily.5. Karyotyping- detect the number ofchromosomes and chromosomalabnormalities.
1. Genetic Counseling- is the process bywhich patients or relatives, at risk ofan inherited disorder, are advised of theconsequences and nature of thedisorder, the probability of developing ortransmitting it, and the options open tothem in management and family planning.This complex process can be separated intodiagnostic (the actual estimation of risk)and supportive aspects
2.Field of Medicine-example: Genetherapy -is the use of DNA as apharmaceutical agent to treat disease.It derives its name from the idea thatDNA can be used to supplement oralter genes within anindividual’s cells as a therapy totreat disease. The most common form ofgene therapy involves using DNA thatencodes a functional, therapeutic genein order to replace a mutated gene.