157 Mutations uitimate Key Idea Mutations are the changes to

157 Mutations uitimate Key Idea: Mutations are the changes to the DNA sequence are calied mutations. source of new genetic variation (ie Mutations are in Utmatelys mutations are the DNA changes no he DNA sequence and occurs arough new parts modifies existing genes and can variation in form of change large source of all new genetic variation. he base, while others There are types of mutation, some change only one nucleoede chromosomes. may harmful those that cause cancer) but causes the most for An example of a mutation producing a wery is de occurs form new NSRD) in The mutation of genetic chadren. a protein called connexin 26. Aptide chain brmed Aaminoacd is read in The gene that codes for the peptide chain connexin 26 is on The most common mutation this gene is in of the 35th Deleting the guanine changes the and code in a short chain, short peptide chain Six connexin 25 peptide chains join to form a connection between The deletion creates a recessive ailele. A person oells. If these not is deaf when they carry two made correctly they cannot form the final structure. 1. (a) Define the term mutation: (b) How do mutations increase genetic variation? 2, identify the type of mutation that has occurred in the DNA sequences shown below: Normal DNA sequence: CCT GAT GCGAAGTTA TCA GTA CCA DNA sequence 1: CCT GAT GCG TTA TCA GTA CCA ccT GAT GCG AAG CCC TTATCA GTA CCA

Solution

IA Mutation: The permanent alteration in the genetic sequenve of the nucleotide sequence of genome or other extrsa chromosomal DNA in an orgsnism is called mutation

IIA Genetic variations due to mutations: Mutations are the raw material for evolution. As each cell contains DNA there are lot places for mutations to take place. When the mutations occur in germ line cells they are transferres to next generation and result in variations.