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GENETICS & PUNNETT SQUARES. Gregor Mendel, an Austrian monk in the 1800s, noticed the following while raising peas in his monastery's garden…. Pea plants of varying sizes TALL plants SHORT plants Pod textures variances SMOOTH pods WRINKLED pods Color variances
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Gregor Mendel, an Austrian monk in the 1800s, noticed the following while raising peas in his monastery's garden… • Pea plants of varying sizes • TALL plants • SHORT plants • Pod textures variances • SMOOTH pods • WRINKLED pods • Color variances • PODS of green and yellow • FLOWERS of white and purple
Mendel set out to understand how these traits were handed down to off-spring plants through controlling the pollination between plants… • Doing so allowed for his discovery of many important GENETIC RULES • How something or someone looks does not always match what their genetic code might suggest! • Genotype – Actual genetic makeup • Phenotype – What they/it looks like • Traits that frequently show up – Dominant • Traits that show up less – Recessive • Combinations - Hybrids
Predictions using PUNNETT SQUARES • Each gene has two chances at a trait • Two Copies • Two Alleles • A HYBRID could carry an allele for a recessive trait even if you cannot see it • EXAMPLE: A TALL plant, tall dominant parent, could have a recessive allele (short) • This is the difference between • GENOTYPE (Actual GENETIC MAKEUP) • & • PHENOTYPE (How It Appears)
PUNNETT SQUARES These are the 2 alleles of each parent plant crossed with one another and showing the 4 possible offspring. TT – Dominant Tall, tt – Recessive Short, Tt – Mixed Hybrid T T T t T T t t TT – Dominant Tall (Geno T, Pheno T) Tt – Mixed Hybrid (Geno H, Pheno T) tt – Recessive Short (Geno S, Pheno S) T T T t • ____ • ____ • ____ • ____ • ____ • ____ • ____ • ____ T t t t • ____ • ____ • ____ • ____ • ____ • ____ • ____ • ____
PUNNETT SQUARES These are the 2 alleles of each parent plant crossed with one another and showing the 4 possible offspring. TT – Dominant Tall, tt – Recessive Short, Tt – Mixed Hybrid T T T t T T t t TT – Dominant Tall (Geno T, Pheno T) Tt – Mixed Hybrid (Geno H, Pheno T) tt – Recessive Short (Geno S, Pheno S) T T T t TT TT Tt TT • ____ • ____ • ____ • ____ • ____ • ____ • ____ • ____ T t t t TT TT Tt tt TT TT tt tt • ____ • ____ • ____ • ____ • ____ • ____ • ____ • ____ Tt Tt tt tt