Upload
rozeka01
View
360
Download
6
Embed Size (px)
DESCRIPTION
Citation preview
Biology
Unit 5 Notes:Mendelian Genetics
(1) Gregor Mendel
• Monk• Studied genetics of pea plants.
• He noticed that:– There were some traits which showed up all of
the time (dominant).– There were some traits which showed up some
times (recessive).– These traits are passed down from parents.– You can’t tell just by looking at an organism,
which genes it has.
(2) Dominant + Recessive Traits
• Dominant Trait:– These will ALWAYS SHOW UP if they are
present.– Representation Capital Letters
• Recessive Trait:– These will ONLY SHOW UP if the organism
inherited 2 together.– Representation Lower Case Letters
(3) Inheriting Traits
• You inherit 2 alleles for every gene.– Gene = Chunk of DNA.– Allele = Variation that chunk can come in.
• “Heterozygous” = You inherited 1-Dominant and 1-Recessive allele.
• “Homozygous” = You inherited 2 of the same alleles.– “Homozygous Dominant” = You inherited 2-Dominant
alleles.– “Homozygous Recessive” = You inherited 2-Recessive
alleles
(4) Ways to Describe Inheritance
• Phenotype:– Physical Description.– Examples:
• “White”• “Brown”• “White and Brown Spotted”
• Genotype:– Genetic Description.– Examples:
• AA or Homozygous Dominant• Aa or Heterozygous• aa or Homozygous Recessive
(5) What’s With These Letters?
• The letters represent the alleles an organism can inherit.
• You should choose letters with a different Capital + Lower Case appearance:– A and a– B and b– Bad Life Choices: S and s, X and x, C and c
• Actual Letters DO NOT MATTER:– Heterozygous needs to be: Capital + Lower– Homozygous Dominant needs to be: 2 Capital– Homozygous Recessive needs to be: 2 Lower