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Notes: Probability and Heredity. Read pgs. 162-167. Objective: Be able to perform a simple Punnett square. Genetics. Heredity: the passing of traits/characteristics from parents to offspring.
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Notes: Probability and Heredity Read pgs. 162-167. Objective: Be able to perform a simple Punnett square.
Genetics • Heredity: the passing of traits/characteristics from parents to offspring. • Genes: the part of the DNA that controls a certain trait or characteristic. Hair color, eye color, freckles, etc.
Alleles • The different forms of a gene, represented by capital and lower case letters. • TT, Tt, tt.
Traits • Dominant Trait: Capital Letter. A trait that always shows up in an organism when it is present. • Recessive Trait: Lower-case Letter. A trait that only shows up in an organism when a dominant trait is not present. Video: Testcross
Dominant and Recessive T=Tall t=Short H=no hair h=hair F=Fan f=non fan
Genotype • Genotype: An organism’s genetic makeup or allele combinations, TT, Tt, tt. • These are the actual genes in your DNA.
Phenotype • Phenotype: an organisms physical appearance or visible traits, tall or short. • This is what you look like or what you see.
Homozygous • Homozygous/Purebred: When an organism has two identical alleles for a trait, TT or tt.
Heterozygous • Heterozygous/Hybrid: when and organism has different alleles for the same trait, Tt. Donkey Video: Zygous Mule Horse
Codominance • Codominance is when alleles are neither dominant nor recessive, but both are expressed. • This helps to explain mixed traits such as a black chicken and a white chicken mating and their offspring are black and white. Video: Codominance
Punnett Square • Punnett Square: A chart that shows all of the possible combinations of alleles from a genetic cross. Video: Punnett Squares
Probability • Probability is a number that describes how likely it is that a certain event will occur. • When flipping a coin, the probability of it landing on heads is 50% and tails is 50%.
Probability • In a Punnett square, each box represents a 25% chance of the offspring receiving that genotype. • Each box represents a 25% chance and there are 4 boxes. 4X25%=100%.
Punnett Square Cross a homozygous tongue roller with a heterozygous tongue roller. Dominant Allele= Recessive Allele= Genotype for homozygous tongue roller= Genotype for heterozygous tongue roller= Genotype outcomes= Phenotype outcomes=
Punnett Square Cross a homozygous tongue roller with a homozygous non-tongue roller. Dominant Allele= Recessive Allele= Genotype for homozygous tongue roller= Genotype for homozygous non-tongue roller= Genotype outcomes= Phenotype outcomes=
Punnett Square Cross a heterozygous tongue roller with a heterozygous tongue roller. Dominant Allele= Recessive Allele= Genotype for heterozygous tongue roller= Genotype for heterozygous tongue roller= Genotype outcomes= Phenotype outcomes=