this note came up in my grade nine science project research (mutation related)?

Question

"Mutation only causes physical changes if it occurs in the sequence of a gene" The book had never before mentioned the sequence of a gene so I want an explanation to what it is and what this means.

Answer 1

I think what they mean is that the mutation will only cause a physical change to occur if the actual code of the gene is changed. To clarify, much of the DNA in our bodies does not code for genes, it is actually "junk DNA" that is leftover from millions of years of evolution. If a mutation occured in the junk DNA, nothing would happen. If a mutation occured in a gene itself, then there would be a physical change. I would also like to point out that I do not think that book is entirely correct. Physical changes can occur with a mutation outside a gene, if the mutation occurs in the region of a transcription factor. However, that is beyond what you would know in ninth grade science :)

Answer 2

In simple terms, genetic information from the DNA blueprint is transcribed into RNA which is used for production of proteins. However, the process is not as easy as that. When the DNA is transcribed into RNA, the RNA produced is denoted as hnRNA (heterogeneous nuclear RNA) or pre-RNA. This precursor single strand material contains both the coding sequences for the gene (exons) but also contains non-coding or filler sequences (introns). The filler sequneces in the pre-RNA are removed and the coding sequences "spliced" (combined together) to make the mature RNA before the molecule leaves the nucleus.

If a mutation in a gene occurs within a non-coding region (i.e. one of the filler intron sequences), then there would be no impact on the final protein product, so the mutation would be masked because it will be removed during removal of the intron. If the mutation is in a coding sequence in the gene (i.e. in an exon), the mutation MAY cause a physical change. There are mutations which are known as "silent mutations" because although there is a change in a nucleotide, there is no change in the amino acid that the nucleotide codes for. For example, the DNA triplet AAA codes for the amino acid phenylalanine. Say there is a mutation of the final A to a C, the resulting AAC triplet also codes for phenlyalanine, so there would be no chance in the final protein sequence...thus the mutation is silent.

This is so much more to this, but hopefully this will give you a basic idea of what the book is speaking of.

Answer 3

Segments of the DNA that do not code for anything are called introns. Any mutation in the intron region will not affect the organism. The mutation will stay for ever. A lethal mutation in an essential gene will cause the death of the fetus and will not be propagated.

Answer 4

first of all
that note is untrue
mutations which occur outside sequence regions (im assuming they mean coding regions) are showing more and more to have huge effects on physical characteristics

and what they probably mean by sequence of a gene is the part which actually gets translated into a protein product

so like in a string of dna you have lots of nucleotides (a,g,t,c) and three of those each code for a specific amino acid....but only sections of amino acids actually get turned into proteins....(these areas are called exons). its hard to describe without a diagram really. but yeh basically..when you think of coding region...think region which ends up being turned into a protein

btw this is a little advanced for grade 9!!!!

Answer 5

This lady in my technology classification did something with birds and colours She taped brightly colored shape paper around some chook feeders (crimson, yellow, blue) and she or he reported which shade had the main takers each few days she'd change the placement of the colours to verify the birds have been going for the colours, not the region would that be seen like animal finding out? wish this helps stable success at the same time with your undertaking