Mutation
- 2. DETAIL ABOUT MUTATION 1)Defination:-dna & structure 2)Mutation:- A)Molecular B)chromosonal 3)Cause of mutation 4)Types of mutation:- A)Somatic B)germ line a)effect of germ line mutation 5)Control gene 6)Sickle cell disease & Trait 7)Role of Bioinformatics
- 3. What is DNA? DNA or deoxyribonucleic acid is the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is calledmitochondrial DNA or mtDNA).
- 4. DNA is made of a long sequence of smaller units strung together. There are four basic types of unit: A, T, G, and C. These letters represents the type of base each unit carries: adenine, thymine, guanine, and cytosine. The sequence of these bases encodes instructions. Some parts of your DNA are control centers for turning genes on and off, some parts have no function, and some parts have a function that we don't understand yet. Other parts of DNA are genes that carry the instructions for making proteins — which are long chains of amino acids. These proteins help build a organism.
- 5. Protein-coding DNA can be divided into codons— sets of three bases that specify an amino acid or signal the end of the protein. Codons are identified by the bases that make them up — in the example at right, GCA, for guanine, cytosine, and adenine. The cellular machinery uses these instructions to assemble a string of corresponding amino acids (one amino acid for each three bases) that form a protein. The amino acid that corresponds to "GCA" is called alanine; there are twenty different amino acids synthesized this way in humans. "Stop" codons signify the end of the newly built protein. After the protein is built based on the sequence of bases in the gene, the completed protein is released to do its job in the cell.
- 7. WHAT IS MUTATION A mutation is a change in DNA, the hereditary material of life. An organism's DNA affects how it looks, how it behaves, and its physiology. So a change in an organism's DNA can cause changes in all aspects of its life. Mutations are essential to evolution; they are the raw material of genetic variation. Without mutation, evolution could not occur.
- 8. Types of mutation Molecular Substitution Insertion Deletion Frameshift Choromosonal Inversion Duplication Translocation
- 9. Now we will look about detail about mutation…
- 10. Substitution A substitution is a mutation that exchanges one base for another (i.e., a change in a single "chemical letter" such as switching an A to a G). Such a substitution could:change a codon to one that encodes a different amino acid and cause a small change in the protein produced. For example,sickle cell anemia is caused by a substitution in the beta- hemoglobin gene, which alters a single amino acid in the protein produced. change a codon to one that encodes the same amino acid and causes no change in the protein produced. These are called silent mutations. change an amino-acid-coding codon to a single "stop" codon and cause an incomplete protein. This can have serious effects since the incomplete protein probably won't function.
- 11. Insertion Insertions are mutations in which extra base pairs are inserted into a new place in the DNA.
- 12. Deletion Deletions are mutations in which a section of DNA is lost, or deleted.
- 13. Frameshift • Since protein-coding DNA is divided into codons three bases long, insertions and deletions can alter a gene so that its message is no longer correctly parsed. These changes are called frameshifts.For example, consider the sentence, "The fat cat sat." Each word represents a codon. If we delete the first letter and parse the sentence in the same way, it doesn't make sense. • In frameshifts, a similar error occurs at the DNA level, causing the codons to be parsed incorrectly. This usually generates truncated proteins that are as useless as "hef atc ats at" is uninformative. • There are other types of mutations as well, but this short list should give you an idea of the possibilities
- 14. Inversion Chromosome segment breaks off Segment flips around backwards Segment reattaches
- 15. Duplication Occurs when a gene sequence is Repeated.
- 16. Translocation • Involves two chromosomes that aren’t homologous. • Part of one chromosome is transferred to another chromosomes
- 18. The causes of mutations 1. DNA fails to copy accurately:- Most of the mutations that we think matter to evolution are "naturally-occurring." For example, when a cell divides, it makes a copy of its DNA — and sometimes the copy is not quite perfect. That small difference from the original DNA sequence is a mutation.
- 19. 2. External influences can create mutations:- Mutations can also be caused by exposure to specific chemicals or radiation. These agents cause the DNA to break down. This is not necessarily unnatural — even in the most isolated and pristine environments, DNA breaks down. Nevertheless, when the cell repairs the DNA, it might not do a perfect job of the repair. So the cell would end up with DNA slightly different than the original DNA and hence, a mutation.
- 20. Types Mutations 1)Somatic mutation:- Since all cells in our body contain DNA, there Are lots of places for mutations to occur However , some mutations cannot be passed on to offspring and do not matter for evolution. Somatic mutations occur in non-reproductive cells and won't be passed onto offspring. For example, the golden color on half of this Red Delicious apple was caused by a somatic mutation. Its seeds will not carry the mutation.
- 21. 2)Germ line mutation:- The only mutations that matter to large-scale evolution are those that can be passed on to offspring. These occur in reproductive cells like eggs and sperm and are called germ line mutations
- 22. Effects of germ line mutations 1. No change occurs in phenotype 2. Small change occurs in phenotype 3. Big change occurs in phenotype
- 23. 1)No change occurs in phenotype. Some mutations don't have any noticeable effect on the phenotype of an organism. This can happen in many situations: perhaps the mutation occurs in a stretch of DNA with no function, or perhaps the mutation occurs in a protein- coding region, but ends up not affecting the amino acid sequence of the protein. 2) Small change occurs in phenotype. A single mutation caused this cat's ears to curl backwards slightly.
- 24. 3)Big change occurs in phenotype. Some really important phenotypic changes, like DDT resistance in insects are sometimes caused by single mutations. A single mutation can also have strong negative effects for the organism. Mutations that cause the death of an organism are called lethals- and it doesn't get more negative than that.
- 25. CONTROL GENE
- 27. Little mutations with big effects: Mutations to control genes Mutations are often the victims of bad press — unfairly stereotyped as unimportant or as a cause of genetic disease. While many mutations do indeed have small or negative effects, another sort of mutation gets less airtime. Mutations to control genes can have major (and sometimes positive) effects. Some regions of DNA control other genes, determining when and where other genes are turned "on". Mutations in these parts of the genome can substantially change the way the organism is built. The difference between a mutation to a control gene and a mutation to a less powerful gene is a bit like the difference between whispering an instruction to the trumpet player in an orchestra versus whispering it to the orchestra's conductor. The impact of changing the conductor's behavior is much bigger and more coordinated than changing the behavior of an individual orchestra member. Similarly, a mutation in a gene "conductor" can cause a cascade of effects in the behavior of genes under its control.
- 28. Many organisms have powerful control genes that determine how the body is laid out. Example- Hox genes are found in many animals (including flies and humans) and designate where the head goes and which regions of the body grow appendages. Such master control genes help direct the building of body "units," such as segments, limbs, and eyes. So evolving a major change in basic body layout may not be so unlikely; it may simply require a change in a Hox gene and the favor of natural selection. Mutations to control genes can transform one body part into another. flies carrying Hox mutations that sprout legs on their foreheads instead of antennae!
- 30. A case study of the effects of mutation: Sickle cell anemia Sickle cell anemia is a genetic disease with severe symptoms, including pain and anemia. The disease is caused by a mutated version of the gene that helps make hemoglobin —a protein that carries oxygen in red blood cells. People with two copies of the sickle cell gene have the disease. People who carry only one copy of the sickle cell gene do not have the disease, but may pass the gene on to their children.
- 31. How Does a Child Get Sickle Cell DIsease? • Sickle cell disease is inherited through genes. Genes contain messages that are passed on to the child through the mother's egg and the father's sperm. These messages control such qualities as eye color, blood type, and the kind of hemoglobin a person will have, etc. • Germs do not cause sickle cell disease and you cannot catch it from another person like you catch a cold. • For a child to have any form of sickling disease, each parent will have an abnormal hemoglobin. One possibility is that each parent has sickle cell trait (AS). Another possibility is when one parent has the disease (SS) and the other parent has sickle cell trait (AS). • In hemoglobin SC disease, one parent has sickle cell trait and the other parent has a different trait (hemoglobin C). In sickle beta-thalassemia, one parent has sickle cell trait (or sickle cell anemia) and the other parent carries the trait for beta thalassemia (or has thalassemia major).
- 32. Where the mutation occur in Anemia Official Gene Symbol: HBB Name of Gene Product: hemoglobin, beta Alternate Name of Gene Product: beta globin Locus: 11p15.5 - The HBB gene is found in region 15.5 on the short (p) arm of human chromosome 11.
- 33. sickle-cell anemia is caused by a single point mutation in the nucleotide sequence of β-globin. The mutation is located in the seventh codon (The first codon codes for Met, the leader amino acid in polypeptides). The seventh triplet should read GAG which colds for glutamic acid, but the middle nucleotide has changed to a thymine, which changes the triplet to GTG, which codes for valine. Replacement of the normally charged glutamic acid with the hydrophobic valine. Replacement of the normally charged glutamic acid with the hydrophobic valine alters the solubility of hemoglobin, so that at a lower oxygen concentration, the altered protein changes the red blood cell to a sickle shape that is unable to carry oxygen. This causes the symptoms of sickle-cell anemia.
- 34. There are effects at the DNA level
- 35. There are effects at the protein level Normal hemoglobin (left) and hemoglobin in sickled red blood cells (right) look different; the mutation in the DNA slightly changes the shape of the hemoglobin molecule, allowing it to clump together.
- 36. Protein Function: Hemoglobin molecules, which reside in red blood cells, are responsible for carrying oxygen from the lungs to various parts of the body for use in respiration. The HBB gene codes for one of the two types of polypeptide chains found in adult hemoglobin. Normal adult hemoglobin is a tetrameric protein consisting of two alpha chains and two beta chains. HBB codes for the beta chain, which is often referred to as beta globin. Mutant beta globin is responsible for the sickling of red blood cells seen in sickle cell anemia
- 37. There are effects at the cellular level >Normal red blood cells are round, soft, and flexible. Since they can squeeze through small blood vessels, blood flows easily. >When red blood cells are shaped like a sickle, they are hard and rigid. These sickled cells can get stuck and plug up small blood vessels. The flow of blood and oxygen can be slowed down or stopped.
- 39. How to get β-globin sequence A. Focus on-actual nucleotide sequence for the β- globin polypeptide. B. This sequence was obtained from GeneBank. C. KEY WORD: HUMHBB D. There are actually 73,308 nucleotides for hemoglobin, which is located at the tip of Chromosome 11. This includes the β-globin gene as well as several other related globin genes . E. The sequence that contains the β -globin information is located between nucleotides 62,137 → 63,660.
- 42. 62,137 - 63,660
- 43. Human β-globin sequence from 62137 → 63660 62137 ACAT TTGCTTCTGA CACAACTGTG 62161 TTCACTAGCA ACCTCAAACA GACACCATGG TGCACCTGAC TCCTGAGGAG AAGTCTGCCG 62221 TTACTGCCCT GTGGGGCAAG GTGAACGTGG ATGAAGTTGG TGGTGAGGCC CTGGGCAGGT 62281 TGGTATCAAG GTTACAAGAC AGGTTTAAGG AGACCAATAG AAACTGGGCA TGTGGAGACA 62341 GAGAAGACTC TTGGGTTTCT GATAGGCACT GACTCTCTCT GCCTATTGGT CTATTTTCCC 62401 ACCCTTAGGC TGCTGGTGGT CTACCCTTGG ACCCAGAGGT TCTTTGAGTC CTTTGGGGAT 62461 CTGTCCACTC CTGATGCTGT TATGGGCAAC CCTAAGGTGA AGGCTCATGG CAAGAAAGTG 62521 CTCGGTGCCT TTAGTGATGG CCTGGCTCAC CTGGACAACC TCAAGGGCAC CTTTGCCACA 62581 CTGAGTGAGC TGCACTGTGA CAAGCTGCAC GTGGATCCTG AGAACTTCAG GGTGAGTCTA 62641 TGGGACCCTT GATGTTTTCT TTCCCCTTCT TTTCTATGGT TAAGTTCATG TCATAGGAAG 62701 GGGAGAAGTA ACAGGGTACA GTTTAGAATG GGAAACAGAC GAATGATTGC ATCAGTGTGG 62761 AAGTCTCAGG ATCGTTTTAG TTTCTTTTAT TTGCTGTTCA TAACAATTGT TTTCTTTTGT 62821 TTAATTCTTG CTTTCTTTTT TTTTCTTCTC CGCAATTTTT ACTATTATAC TTAATGCCTT 62881 AACATTGTGT ATAACAAAAG GAAATATCTC TGAGATACAT TAAGTAACTT AAAAAAAAAC 62941 TTTACACAGT CTGCCTAGTA CATTACTATT TGGAATATAT GTGTGCTTAT TTGCATATTC 63001 ATAATCTCCC TACTTTATTT TCTTTTATTT TTAATTGATA CATAATCATT ATACATATTT 63061 ATGGGTTAAA GTGTAATGTT TTAATATGTG TACACATATT GACCAAATCA GGGTAATTTT 63121 GCATTTGTAA TTTTAAAAAA TGCTTTCTTC TTTTAATATA CTTTTTTGTT TATCTTATTT 63181 CTAATACTTT CCCTAATCTC TTTCTTTCAG GGCAATAATG ATACAATGTA TCATGCCTCT 63241 TTGCACCATT CTAAAGAATA ACAGTGATAA TTTCTGGGTT AAGGCAATAG CAATATTTCT 63301 GCATATAAAT ATTTCTGCAT ATAAATTGTA ACTGATGTAA GAGGTTTCAT ATTGCTAATA 63361 GCAGCTACAA TCCAGCTACC ATTCTGCTTT TATTTTATGG TTGGGATAAG GCTGGATTAT 63421 TCTGAGTCCA AGCTAGGCCC TTTTGCTAAT CATGTTCATA CCTCTTATCT TCCTCCCACA 63481 GCTCCTGGGC AACGTGCTGG TCTGTGTGCT GGCCCATCAC TTTGGCAAAG AATTCACCCC 63541 ACCAGTGCAG GCTGCCTATC AGAAAGTGGT GGCTGGTGTG GCTAATGCCC TGGCCCACAA 63601 GTATCACTAA GCTCGCTTTC TTGCTGTCCA ATTTCTATTA AAGGTTCCTT TGTTCCCTAA
- 44. There are 1,473 nucleotides in the gene, enough to code for 491 triplet codons. But the β-globin polypeptide has just 146 amino acids.The excess nucleotides are “introns” (intervening sequences) that separate the protein coding "exons“ (expressed sequences). The β-globin gene consists of three exons and two introns. Exon #1 62187 – 62278 Intron #1 62279 – 62409 Exon #2 62410 – 62631 Intron #2 62632 – 63481 Exon #3 62482 – 63610
- 46. Open google Type- NCBI goto EMBL-EBI TOOLS SEQUENCE ANALYSIS SELECT:- TRANSEQ
- 47. Sequence Translation is used to translate nucleic acid sequence to corresponding peptide sequences. 1)Transeq (EMBOSS):-EMBOSS Transeq translates nucleic acid sequences to the corresponding peptide sequences. 2) Sixpack (EMBOSS):-EMBOSS Sixpack displays DNA sequences with 6-frame translation and ORFs.
- 48. Back-translation is used to predict the possible nucleic acid sequence that a specified peptide sequence has originated from. 1) Backtranseq (EMBOSS):-EMBOSS Backtranseq back-translates protein sequences to nucleotide sequences. 2) Backtranambig (EMBOSS):-EMBOSS Backtranambig back- translates protein sequences to ambiguous nucleotide sequences.