3. Defination of genetics variation.
• genes. Genetic variation means that biological systems – individuals and
populations – are different over space. Each gene pool includes various allels
of genes.The variation occurs both within and among population, supported
by individual carriers of the variant
• Genetic variation is brought about, fundamentally, by mutation, which is
a permanent change in the chemical structure of chromosomes.gene
recombination also produces changes within alleles.
5. SOURCES:The 4 types of genetic variation are
1) mutation- is the mutation of a gene. this is really rare, most mutations are in the recessive trait so they
are hidden by a dominant trait. Most mutations have no effect but some can be harmful and very few have
positive effects.
2 ) Genetic recombination- is the formation of new conbinations of alleles during sexual reproduction.
This happens alot during crossing over. Every one is different because you get a mix of genes from your mom
and dad.
3) migration- is when an individual who moves into a population brings different genes that may not be
present in the population, it has the most effect on a small population.
4) Genetic drift- when a few individuals have a trait that the rest of the population doesn't have and if
these organisms die off without mating, then they die in the gene pool. this reduces variation in a population so it
makes less evolution
6. VARIATION AND MUTATION
• Continuous Variation
• Small differences between individuals
• Greatly affected by environment
• e.g. height, shoe size, length of hair plotted on a line graph
• Discontinuous Variation
• Differences that are classed or categorised
• Not greatly affected by environment
• e.g. blood group, sex, hair colour, eye colour plotted on a bar chart or pie chart
• Causes: climate, diet, lifestyle, culture, accidents
7. Environmental variation
Environment affects how our inherited characteristics develop
Twins who grow up separately might become very different: e.g. fashion, taste, hair
colour, build, personality, aptitudes
• Genetic Variation
• Causes:
• Mixing of parent information during meiosis
• Gamete forms from a unique combination of genetic information
• Siblings can have both similar and very different traits
• They are mixtures of their parents, each sibling can receive different characteristics
of their parents e.g. natural hair colour, eye colour, blood type
8.
9. MUTATION VARIATION
During replication, an organism’s genetic make-up (DNA) can change or
mutate. Changes to genes are called mutations. Mutations can be
spontaneous (they just happen). They can also happen because of:
•Radiation
•Chemicals, such as tar from cigarette smoke
If mutation is large then the organism will probably not survive to reproduce
If mutation is small then change might be beneficial. Offspring will flourish,
doing better than others in that species. Many more offspring will inherit this
beneficial mutation and will be better suited to that environment
10.
11. Chromosomal mutation
1:Mutation deletion
• deletion mutations. (genetics) A type of mutation wherein one or few
nucleotide base pairs are deleted or lost from a chromosome especially
during the replication of genetic material. Supplement. Mutation is a change
in the nucleotide sequence of a gene or a chromosome.
12. 2:Duplication mutation
• Duplication mutations occur when a DNA sequence is duplicated or
replicated resulting in multiple copies in the region.
13. 3:Inversion Mutation
• Inversion mutation definition
• An Inversion mutation is a mutation that causes a reversal
in the order of a segment of
a chromosome within the chromosome,
or a gene.
14. 4:Translocation mutation definition
Translocations mutations occur in
chromosomes,
wherein chromosome segments change positions.
It can either take place within a chromosome or
between chromosomes. Translocations mutations
occur in chromosomes, wherein chromosome
segments change positions.
15. Gene mutation
1:Insertion mutation definition
Insertion mutation. Mutation is a change in the nucleotide sequence of a gene or a
chromosome. Based on the effect of mutation on the gene structure, mutations may be: (1)
small-scale mutations or (2) large scale mutations. Small-scale mutations are a type of
mutation where one or few nucleotides of a gene are affected.
16.
17.
18. Mechanisms for genetics variation
• Five mechanis, that can lead to micro envolution
• Mutation
• Genetics drift
• Gene flow
• Non random mating
• Natural selection
19.
20. The impt.of genetics variation
• As previously discussed, genetics variation is impt. Because it allow
individuals with in a given species to adopt to their environment.
• Remember we are born with adaptation if do not naturally have these
difference in our DNA we can not obtain them.
21. Role in health/pharmacology
Gene therapy: gene therapy is an experimental tech.that use to treat or prevent
disease.
Approaches are
replacing a mutated gene
Inactivating mutated gene
Introducing new gene
Gene repair therapies
Vector for gene transfer: