2.4 variation and inheritance

• variation


  differences between individuals in a population
• phenotype


  visible characteristics of an organism with occur as a result of its genes
• genotype


  pair of alleles which control 1 characteristic
• discrete variation / single gene inheritance


  traits that exhibit distinct groups, only 1 gene controls that characteristic
• continuous variation / polygenic inheritance


  traits that can have a range of values between a min + max, many genes are controlling that characteristic
• genetics


  study of variation and inheritance in biology
• allele


  version of a gene
• gene


  sequence of dna on a chromosome
• homozygous


  when a genotype has 2 same alleles
• heterozygous


  when a genotype has 2 different alleles
• dominant


  when an allele is always seen in the phenotype if its present
• recessive


  when an allele is only seen in the phenotype if there are 2 present
• P generation


  true breeding parents
• F1 generation


  hybrids
• F2 generation


  3:1, crossed between 2 hybrids
• monohybrid cross


  cross between 2 organisms with different variations