inheritance notes page 27. fyi practice summarizing! do not copy word-for-word. if you run out of...
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FYI
• Practice summarizing! Do not copy word-for-word.
• If you run out of space, do NOT go to the next page. Attach a piece of paper to page 27.
Gregor Mendel
• Called the “Father of Genetics”
• Studied many different characteristics of pea plants
• Examples: flower color and plant height
• His experiments with pea plants helped us understand how traits are inherited
• He thought there was “something” in each plant that controlled its traits
• That “something” is known today as genes
Genes
• Every characteristic is controlled by 2 genes• 1 gene is from the mother
• 1 gene is from the father
Allele
• An allele is a form of a gene• There are 2 possible forms
• dominant or recessive
• Capital letters represent dominant alleles (P, G, T)
• Lowercase letters represent recessive alleles (p, g, t)
Dominant vs. Recessive Genes
• Dominant• An offspring that
inherits one or more dominant genes will show the dominant trait.
• Dominant genes will mask (cover up) a recessive gene.
• Recessive• An offspring that
inherits 1 recessive gene from 1 parent and 1 recessive gene from the other parent will have 2 recessive genes. This means that there is no dominant gene to mask the recessive trait in the offspring.
Phenotype
• Describes an organism’s physical appearance (what the trait looks like)• Example: blue eyes, purple flower, etc.
Homozygous Genotype
• The prefix ‘homo’ means ‘same’
• Both alleles in a genotype are the same• Both are dominant OR both are recessive
• Mendel’s parent generation plants were homozygous• GG = green peas
• gg = yellow peas
Homozygous Genotype Continued
•Homozygous dominant• Both alleles are dominant
• Example: GG
•Homozygous recessive• Both alleles are recessive
• Example: gg
Heterozygous Genotype
• The prefix ‘hetero’ means ‘different’
• The alleles in a genotype are different• One is dominant and one is recessive
• Mendel’s F1 generation plants were heterozygous• Gg = green peas
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