Probability and The Punnett Square Gaiser Life Science
Dec 17, 2015
Know
Evidence
Page 37
Probability and The Punnett Square
What are the chances of flipping a coin and landing on tails?Explain your answer.
The Punnett Square
Clarifying ?s Information
Page 38
probability - The chance/likelihood that something will happen- The chance/likelihood that something will happen
- a chart that shows all possible genetic crosses- a chart that shows all possible genetic crosses
Example: flipping a coin – 50/50 chance of landing on heads (50/50, 1 in 2, 1:1, ½, 50%)
Example: Dad’s alleles = Tt, Mom’s alleles = TT
Punnett Square
- Mendel was the first scientist to determine that probability could be used to predict genetic crosses.
used to determine the probability of a specific outcome
T t
T TT Tt
T TT tT
25% 25%
25% 25%
1 in 4 chance of a specific outcomeOffspring has a 100% chance of being tall.
Probability and The Punnett Square
- Reginald C. Punnett originated the Punnett Square.
Clarifying ?s Information
Page 39
Summary:
- an organism’s genetic make-up
- an organism’s physical appearance/visible traits
- two identical alleles
pheno = physical
genotype
phenotype
homozygousExample: TT or tt
Example: Tt
heterozygous - two different alleles
codominance - alleles are neither dominant or recessive – both show up in offspring
Example: being tall
Example: Tt
Example: black chickens & white chickens – the offspring have both black and white feathers
Probability and The Punnett Square
Page 38
Clarifying ?s InformationProbability and The Punnett Square
probability - The chance/likelihood that something will happen- The chance/likelihood that something will happen
- a chart that shows all possible genetic crosses- a chart that shows all possible genetic crosses
Example: flipping a coin – 50/50 chance of landing on heads (50/50, 1 in 2, 1:1, ½, 50%)
Example: Dad’s alleles = Tt, Mom’s alleles = TT
Punnett Square
- Mendel was the first scientist to determine that probability could be used to predict genetic crosses.
used to determine the probability of a specific outcome
1 in 4 chance of a specific outcomeOffspring has a 100% chance of being tall.
- Reginald C. Punnett originated the Punnett Square.
T t
T TT Tt
T TT tT
25% 25%
25% 25%
Page 39
Clarifying ?s Information
Summary:
Probability and The Punnett Square
- an organism’s genetic make-up
- an organism’s physical appearance/visible traits
- two identical alleles
pheno = physical
genotype
phenotype
homozygousExample: TT or tt
Example: Tt
heterozygous - two different alleles
codominance - alleles are neither dominant or recessive – both show up in offspring
Example: being tall
Example: Tt
Example: black chickens & white chickens – the offspring have both black and white feathers
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