Topic 8
- Created by: Sailing26880
- Created on: 01-05-18 18:17
View mindmap
- Topic 8
- Genetic Variation
- Random Genes
- Random Assortment: of parental chromosomes
- Crossing over: Swapping of DNA between chromosomes
- Random Fertilization: between sperm and egg
- Keywords
- Genotype: the genes
- Phenotype: the physical characteristicof the organism
- Homozygous: both alleles the same
- Heterozygous: 2 alleles for the gene are different
- Dominance: phenotype expressed all the time
- Recessive: only expressed when 2 alleles are the same
- Codominant: where both aleles influence the phenotype
- Multiple alleles: when there are 2 alleles which code for a trait ABO blood
- Codominant: where both aleles influence the phenotype
- Recessive: only expressed when 2 alleles are the same
- Dominance: phenotype expressed all the time
- Heterozygous: 2 alleles for the gene are different
- Homozygous: both alleles the same
- Phenotype: the physical characteristicof the organism
- Genotype: the genes
- Random Genes
- Genetic Diagrams
- Genetic Crosses
- Pedigree Diagrams
- Di-hybrid Inheritance
- 2 non-linked genes are inherited indendently of each other
- Autosomal Linkage
- Any chromosome not involved in the inheritance of sex found on the same chromosome
- Sex Linkage
- Males XY, females **, males more likely to have genetic diseases
- Chi Squared
- expected vs observed
- Selection Pressure
- Directional: moves the value of a characteristic in one direction changes the whole population
- Stabilising: Acts against change by making favourable characteristic more common in an unchanging environment
- Disruptive: leads to a change making the extreme values of a characteristic more common
- Genetic Drift
- Change of alleles due to chance not selection; due to random sexual reproduction; accidents preventing reproduction; alleles not passed on; effects greater in small populations; not not directional
- Population
- Founder effect
- a new population is established by a few individuals so the frequency of alleles is different
- Population Bottleneck
- only a small number of individuals survive a major event, the frequency of alleles is different within the surviving population
- Founder effect
- Hardy Weinberg Equation
- Allele frequency's should be constant through generations as long as: -there is no mutations -random mating -a large population - no migration -no selection pressures
- Genetic Variation
Comments
No comments have yet been made