Genetics Definitions

  • Genes: portion of the DNA molecule that codes for a particular protein.
  • Loci: location in the DNA molecule of the gene
  • Alleles: forms of a gene
  • Homozygous: paired alleles are identical
  • Heterozygous: paired alleles are different
  • Genotype: set of all alleles (i.e. genetic expression)
  • Phenotype: all observable traits (i.e. physical expression)
  • Genome: The complete set of chromosomes for an organism.

Can We Write Your Essay?

Ace your next assignment with help from a professional writer. Free proofreading and copy-editing included.

Genetic Variation

  • Species that possess a greater number of genes have the potential for increased genetic diversity
  • Similarly, the greater the number of different alleles for these genes, the greater the extent of genetic variation there will be within a species and from individual to individual
  • Genetic diversity within a population increases enormously through sexual reproduction, as the various alleles from two parents recombine in each offspring

Hardy-Weinberg Principle

  • Gene pool: The total number of all alleles within a population.
  • Allele frequency: Within a species, the proportion of gene copies in a given allele.
  • Population geneticists developed a method to quantify a gene pool by measuring allele frequency.

Hardy-Weinberg Formula


The Hardy Weinburg Principle

  • Allele frequency will not change from generation to generation as long as:
  • The population remains large.
  • Mating opportunities are equal.
  • No mutations occur.
  • No migration occurs.
  • No natural selection occurs. ie. All individuals have an equal chance at reproducing.

Sample Questions

  • 1) A population has only two alleles, R and r, for a particular gene. The allele frequency of R is 30%. What are the frequencies of RR, Rr, and rr in the population?
  • 2) A population has only two alleles, A and a, for a particular gene. The allele frequency of a is 25%. How many would have the genotypes of AA, Aa, and aa in a population of 150?
READ:
Meiosis: Purpose and Process

  • 1) 0.09 RR, 0.42 Rr, 0.49 rr
  • 2) 84.375 AA, 56.25 Aa, 9.375 aa

Can We Help with Your Assignment?

Let us do your homework! Expert writers in all subject areas are available and will meet your assignment deadline.

guest
0 Comments
Inline Feedbacks
View all comments