Mutation Changing your genes

Mutation defined A Mutation occurs when a DNA gene is damaged or changed in such a way as to alter the genetic message carried by that gene. A Mutation occurs when a DNA gene is damaged or changed in such a way as to alter the genetic message carried by that gene. Example to right the enzyme that is catalyzing the production of flower color pigment has been altered in such a way it no longer catalyzes the production of the red pigment. Example to right the enzyme that is catalyzing the production of flower color pigment has been altered in such a way it no longer catalyzes the production of the red pigment.

Types of Mutation Gene mutation Gene mutation Chromosome mutation Chromosome mutation

Gene Mutation Gene mutation Gene mutation –most common –within a gene –one or more points changed –Base(s) can be  Substituted  Deleted  Added –Result: protein with 1 or more errors

Gene Mutation an Analogy A sentence with three letter words, like the triplet codes in DNA. A sentence with three letter words, like the triplet codes in DNA. –“The fat cat ate the rat” makes sense  Gene mutation substitution –Substitute an ‘a’ for an ‘o’. –“The fat cot ate the rat” nonsense, but only one word affected –Result: Protein may still be able to function

Gene Mutation an Analogy continued –“The fat cat ate the rat” makes sense  Gene mutation deletion –Remove the first ‘a’. –“The ftc ata tet her at” nonsense, and many words affected. –Result: Protein most likely will not function How would an addition/insertion affect the resulting amino acids?

Chromosomal Mutations Change in structure of an entire chromosome Change in structure of an entire chromosomeor Change in chromosome number

Chromosomal Mutations continued Changes in chromosomal structure Changes in chromosomal structure –A chromosome can become tangled during cell division thus rearranging the segments –Five possibilities can happen  Translocation  Inversion  Deletion  Duplication  Addition

Chromosomal structure Translocation Translocation –Segment of one chromosome is transferred to another

Chromosomal structure Inversion Inversion –Segment is rotated so the order of the genes is reversed

Chromosomal structure Deletion Deletion –A segment breaks off so genes are lost

Chromosomal structure Duplication Duplication –A batch of genes are duplicated so now have double of these genes

Chromosomal structure Addition Addition –Repetition of genes on a homologue

Chromosomal Mutations continued Change in chromosome number Change in chromosome number –Two types  Polyploidy  Nondisjunction

Chromosome number Polyploidy Polyploidy –Mostly in plants –Multiples of ‘n’  (3n, 4n, 5n) –Improper separation during meiosis –Often yields larger fruit

Chromosome number Nondisjunction Nondisjunction –Misplacement of a whole chromosome during meiosis –Results  Trisomy or 2n +1 ex: Down’s Syndrome  Monosomy or 2n -1 ex: Turner’s Syndrome