18.1 - Population Genetics Flashcards
What is a population
a group of organisms of the same species that occupies a particular space at a particular time and that can potentially interbreed.
What is a gene pool
All the alleles of all the genes of all the individuals in a population at a given time
Allelic frequency
The number of times an allele occurs within the gene pool
What does cystic fibrosis cause
the mucus produced by affected individuals is thicker than normal.
What is BB
Dominant homozygous
What is Bb
Heterozygous
What is bb
Recessive homozygous
Complete the punnet square to find what % of the population express the phenotype
What is the Hardy-Weinberg principle and what is it used for
- mathematical equation
- used to calculate the frequencies of the alleles of a particular gene in a population.
What is the assumption that the Hardy-Weinberg principle works on
- The proportion of dominant and recessive alleles of any gene in a population remains the same from one generation to the next
- provided that:
1) No mutations arise.
2) The population is isolated, that is, there is no flow of alleles into or out of the population.
3) There is no selection, that is, all alleles are equally likely to be passed to the next generation.
4) The population is large.
5) Mating within the population is random.
Define allele
Different versions of the same gene
Define dominant
Expressed in the phenotype, even if only one copy of the allele is present
Define recessive
Only expressed in the phenotype if two copies of the allele are present
Define homozygous
2 copies of the same allele are present in the genotype
Define heterozygous
2 alleles present in the genotype are different to each other
Define genotype
The combination of alleles and organism possesses for a specific gene
Define phenotype
Physical expression of a gene, determined by genotype and environmental influences
What must happen for evolution to occur
- for evolution to occur in real populations, some of the gene frequencies must change with time
What is the equation used to work out allelic frequency
What is the equation for genotype frequency
If 60% of the alleles in a population (at Hardy Weinberg equilibrium) are dominant, what % of the population would you expect to be:
A) homozygous dominant
B) Heterozygous
C) Homozygous recessive
