P ROBABILITY AND G ENETICS 11/24/14 Mr. Faia 6 th Grade Science

P RINCIPLES OF P ROBABILITY Probability is the likelihood that a particular event will occur What 3 ways can probability be written?

P RINCIPLES OF P ROBABILITY The laws of probability predict what is LIKELY to happen Does NOT predict what WILL happen Each probability event is independent

M ENDEL AND P ROBABILITY Mendel was the 1 st to use the principles of probability to predict the results of genetic crosses What were Mendel’s probability outcomes in the F 1 generation?

P UNNETT S QUARES Punnett Squares show all possible combinations of alleles Used to determine genetic probability

P UNNETT S QUARES Dominant alleles are symbolized with a capital letter Recessive alleles with a lower case letter

P UNNETT S QUARES Create a Punnett Square:

P HENOTYPES AND G ENOTYPES Phenotype is a physical appearance, or visible traits Genotype is a genetic makeup or allele combination

P HENOTYPES AND G ENOTYPES Organism with 2 identical alleles for a trait is homozygous Organism with 2 different alleles for a trait is heterozygous

C ODOMINANCE In codominance, alleles are neither dominant or recessive Some examples are found in chickens, cats, dogs, and flowers

C ODOMINANCE Create a Codominant Punnett Square:

REVIEW What is probability? How can genetics relate to probability? How are Punnett Squares useful to genetecists? Define phenotype. Define genotype. How are genotypes and phenotypes different? Define codominance.