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Genetics gr 9_053811.pptx
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- 3. Genetics • The studyof heredity. • Traits & Characteristics • Heredity – study of how traits are passed between generations.
- 4. • Father ofGenetics - Monk in Austria in mid 1800’s - Worked on common traits in pea plants Gregor Mendel
- 5. 7 Traits inPea plant • Height, flower position, flower color, seed color, seed shape, pod color, pod shape. • Each trait has two forms.
- 6. 7 Traits inPea plant
- 7. Genes • These traitsthat Mendel saw were caused by genes. • A gene is a piece of DNA that determines what protein a cell will make. • Your genes determine what you look like by deciding what proteins your cells make.
- 8. Your chromosomes containmany genes
- 9. Alleles • A genecan take two different forms called alleles - Height gene - 2 alleles – tall and short • An allele is either dominant of recessive - If dominant it will always show when present. - If recessive it will be hidden by the dominant allele
- 10. Alleles • Symbols areused when showing a genetic cross - usually the first letter of the dominant trait is used in upper and lower case Height Gene “A” “a”
- 11. Alleles • For everygene, an organism has 2 copies of that gene on homologous chromosomes from each parent (these are alleles) - a tall pea plant may have two dominant alleles (TT) or one dominant and one recessive allele (Tt) - A short pea plant can only have two recessive alleles (tt)
- 13. Genotype • The geneticmakeup of an individual • The genes they possess represented by letters. • A physical characteristic •What an individual looks like. Phenotype
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