Genetic Mutations

By Nicholas Tucker

Main idea

In biology, a mutation is a permanent alteration of the biology, a mutation is a permanent alteration of the nucleotide sequence of the genome of an organism,virus, of extrachromosomal DNA or other genetic elements. Mutations result from damage to DNA which is not repaired, errors in the process of replication, or from the insertion of deletion of segments of DNA by mobile genetic elements, or other genetic elements.


"Mutations can involve the duplication of large sections of DNA, usually through genetic recombination.These duplications are a major source of raw material for evolving new genes, with tens to hundreds of genes duplicated in animal genomes every million years. Most genes belong to larger gene families of shared ancestry, known as homology. Novel genes are produced by several methods, commonly through the duplication and mutation of an ancestral gene, or by recombining parts of different genes to form new combinations with new functions."

Types of Mutations


Thomas Hunt Morgan

Thomas Hunt Morgan was born on September 25, 1866, at Lexington, Kentucky, U.S.A. He was the eldest son of Charlton Hunt Morgan.He was educated at the University of Kentucky, where he took his B.S. degree in 1886, subsequently doing postgraduate work at Johns Hopkins University, where he studied morphology with W. K. Brooks, and physiology with H. Newell Martin.As a child he had shown an immense interest in natural history and even at the age of ten, he collected birds, birds' eggs, and fossils during his life in the country; and in 1887, the year after his graduation, he spent some time at the seashore laboratory of Alphaeus Hyatt at Annisquam, Mass. During the summer of 1888, he was engaged in research for the United States Fish Commission at Woods Hole.In 1890 he obtained his Ph.D. degree at Johns Hopkins University. in that same year he was awarded the Adam Bruce Fellowship and visited Europe, working especially at the Marine Zoological Laboratory at Naples which he visited again in 1895 and 1900.The importance of Morgan's earlier work with Drosophila was that it demonstrated that the associations known as coupling and repulsion, discovered by English workers in 1909 and 1910 using the Sweet Pea, are in reality the obverse and reverse of the same phenomenon, which was later called linkage. Morgan's first papers dealt with the demonstration of sex linkage of the gene for white eyes in the fly, the male fly being heterogametic. His work also showed that very large progenies of Drosophila could be bred. The flies were, in fact, bred by the million, and all the material thus obtained was carefully analysed. His work also demonstrated the important fact that spontaneous mutations frequently appeared in the cultures of the flies. On the basis of the analysis of the large body of facts thus obtained, Morgan put forward a theory of the linear arrangement of the genes in the chromosomes, expanding this theory in his book, Mechanism of Mendelian Heredity (1915).

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