What is mutation A mutation is a change
- Slides: 51
What is mutation? A mutation is a change in the genetic material that controls heredity. What is genetic materials? relationship is the genetic material and chromosome?
Genetic material and chromosome
homologous
Mutation Results from unrepaired damage to DNA Mutation = Damage - repair
Facts of mutation Mutation are stably inherited changes in the nucleotide sequence of the genome A change in nucleotide sequence due to, for example, damage to DNA is not a mutation unless it caused changes in DNAs that result from replication of the damage DNA.
Mutation or polymorphism DNA sequence variations are sometimes described as mutations and sometimes as polymorphisms. What is the difference between these terms and how are they applied to the human genome?
Polymorphism DNA sequence variation that is common in the population NO standard sequence but two or more equally acceptable alternatives The arbitrary cut-off point between a mutation and a polymorphism is 1 % That is, to be classed as a polymorphism, the least common allele must have a frequency is lower that this, the allele is regarded as a mutation.
ชนดของ mutation การแบงแยกตามขนาดทเกดขน ◦ Point mutation (gene mutation) ◦ Chromosome mutation แหลงกำเนด ◦ Spontaneous mutation ◦ Induced mutation ผลกระทบ ◦ Missense mutation ◦ Nonsense ◦ Frame shift mutation ◦ Lethal mutation
English peppered moths
base substitution deletion / addition
�������� (sickle-cell anemia)
Mutations Germ-line mutation ◦ sperm and egg gamete cells ◦ precursor cell ���������� หากเกดการกลายพนธในเซลลสบพนธ เมอเกดการผสมพนธ (fertilization) �������������������������� ������� Somatic mutation ◦ early or late stages of embryonic development ◦ single embryonic cell ◦ timing of mutation ◦ genetic mosaic
Somatic mutation
Translocation, duplication and deletion
Aneuploidy, euploidy
Spontaneous deamination of cytosine and 5 -methylcytocine hot spots for mutation
Tuatomeric shifts
Chemical mutagen Nitrous acid (HNO 2): ������������ (keto group) ���������� deamination deaminates base ◦ การเปลยนเบส cytocine ���� uracil ◦ ������� adenine ���� hypoxanthine
Chemical mutagen (��� ) Nitrogen mustard ��� ethyl methanesulfonate (EMS): �������� alkyl ������ methyl ����������������� alkylating agent Acridine dye ���� proflavin: ����� frameshift mutation intercalates within DNA helix
Compounds ���� 5 -bromouracil (5 BU) ��� 2 -aminopurine: 5 BU ���� T �������� A ��� G ���� 2 aminopurine ���� A �������� T ��� C ����� DNA replication ����� transition base analogue Chemical mutagen
I. DNA damage from environmental agents Modifying nucleotide bases When the DNA strands are separated and copied. The altered base will pair with an incorrect base and cause mutation. Breaking the phosphate backbone (phosphodiester bond)
Breaking the phosphate backbone - Breaking the phosphate backbone of DNA within a gene crates a mutated form of the gene - It is possible that the mutated gene will produce a protein that differently - Cells with broken DNA will attempt to fix the broken ends by joining these free ends to other pieces of DNA within the cell - This creates a type of mutation called “translocation”. If a functions translocation breakpoint occurs within or near a gene that genes function may be affected
II. Mistakes created during DNA replication Mutations results when the DNA polymerase makes a mistake. Which happens about once every 100, 000 bases.
E. coli § DNA polymerase I and III involved in normal DNA replication § DNA polymerase II, IV and V play a role in DNA repair and the replication of damaged DNA § DNA polymerase III contains a 3’ exonuclease site that remove mismatched bases.
Unusual features of DNA polymerase function The synthesis of DNA at the replication fork Okazaki fragment (100 to 200 nucleotide) § to complete the synthesis of Okazaki fragments § removal of RNA primers § synthesis of DNA in the area where the primers have been removed § the covalent attachment of adjacent fragments of DNA § DNA polymerase I has a 5’ to 3’ exonuclease activity § DNA ligase catalyzes a covalent bond
A three-dimensional view of DNA replication Primosome = helicase + primase Replisome = primosome + two DNA polymerase III § The term dimeric DNA polymerase is two DNA polymerase holoenzymes that move as a unit toward the replication fork. § the lagging strands is looped out.
The proofreading function of DNA polymerase § fidelity: DNA polymerase III is so high because the hydrogen bonding between G and C or A and T is much more stable than between mismatched paris. (one mistake per 10, 000 nucleotides) § proof reading function of DNA polymerase III decrease the error rate to a range of 1 in 100, 000 to 1 million. § proof reading occurs by the removal of nucleotides in the 3’ to 5’ direction at the 3’ exonuclease site (one mistake per 100 million)
The polymerase slippage model
Mutation and the next generation There are two places where mutation can be introduced and carried into the next generation. A mutation occurs in the developing germ line cell, it may persist until that individual reaches reproductive age. A mutation being passed on from parents during meiosis.
Mutation and the next generation Mutations also provide a species with the opportunity to adapt to new environments, as well as to protect a species from new pathogens. ◦ “survival of the fittest”, the basic theory of evolution proposed by Charles Darwin in 1859. ◦ Viral genes have high mutation to serve the virus well by enabling adaptive traits, such as changes in the outer protein coat so that it can escape detection and thereby destruction by the host’s immune system. Viruses also produce infection for infection of a host cell. A mutation within such as enzyme may result in a new form that still allows the virus to infect its host but that is no longer blocked by an anti-viral drug. this will allow the virus to propagate freely in its environment.
- Chromosomal mutation vs gene mutation
- Rocks change due to temperature and pressure change
- Whats the difference between physical and chemical changes
- Is chopping wood a physical change
- Reactive change is change that
- Examples of chemical changes
- Whats the difference between chemical and physical change
- Input and output markets
- Climate change 2014 mitigation of climate change
- Examples of physical vs chemical changes
- Absolute change and relative change formula
- Chemical changes in baking
- How does a physical change differ from a chemical change? *
- Supply and demand curve shifts
- Spare change physical versus chemical change
- Intergers
- First and second order change in education
- Enagic compensation plan
- Painting the wall physical change or chemical change
- What kind of mutation
- 4 steps of protein synthesis
- Competent programmer hypothesis
- Frameshift mutation
- Human
- Hox gene mutation in drosophila
- Mutation and adaptation
- It is a process of change through time
- What is the result of a substitution mutation?
- Insertion frameshift mutation
- Sickle cell anemia mutation
- Karyotype mutations
- Genetic disorders
- Vowel mutation
- Xyy syndrome
- Dna mutation
- Chromosome mutation types
- Chromosomal mutation deletion
- Data flow and mutation testing
- What is somatic mutation
- Mutation isosemantique
- Chromosomal mutation
- Silent mutation
- Noitin
- Robertsonian translocation
- Tautomeric shift mutation
- What does it mean
- Synonymous vs nonsynonymous mutation
- Forward mutation
- Induced mutation
- Chapter 12 section 4: gene regulation and mutations
- Frameshift mutation
- Brca gene mutation