Genetics
The study of heredity (the passing on of genes) in an organism
,Genes and alleles
• Gene = a section of DNA that codes for a protein
• Alleles = different versions of the same gene
• Each cell contains 2 of each kind of chromosome since 23 are maternal and 23 are
paternal therefore each cell has 2 of each kind of gene hence there are different versio
for every trait = allele
• Alleles = same locus. Dominant traits = uppercase letter. Recessive trait = lowercase le
• A recessive trait is only expressed in the offspring when both recessive alleles are pres
• Gene pool = the full set of all the genes or genetic material in a sexually reproducing
population
• Large gene pool = large genetic variety, higher chance of survival
• Small gene pool = minimal genetic variety, less chance of survival
,Zygosity
• Homozygous = both alleles are the same for a particular trait
• Heterozygous = a pair of alleles are different for a particular trait
, …types
• Genotype = all genes an organism has on its chromosomes…the
zygosity BB or Bb or bb
• Phenotype = the physical appearance of an organism, which is
determined by the genotype and external / environmental factors
The study of heredity (the passing on of genes) in an organism
,Genes and alleles
• Gene = a section of DNA that codes for a protein
• Alleles = different versions of the same gene
• Each cell contains 2 of each kind of chromosome since 23 are maternal and 23 are
paternal therefore each cell has 2 of each kind of gene hence there are different versio
for every trait = allele
• Alleles = same locus. Dominant traits = uppercase letter. Recessive trait = lowercase le
• A recessive trait is only expressed in the offspring when both recessive alleles are pres
• Gene pool = the full set of all the genes or genetic material in a sexually reproducing
population
• Large gene pool = large genetic variety, higher chance of survival
• Small gene pool = minimal genetic variety, less chance of survival
,Zygosity
• Homozygous = both alleles are the same for a particular trait
• Heterozygous = a pair of alleles are different for a particular trait
, …types
• Genotype = all genes an organism has on its chromosomes…the
zygosity BB or Bb or bb
• Phenotype = the physical appearance of an organism, which is
determined by the genotype and external / environmental factors
