Launch

•What is the ratio of a diploid cell to a human cell in a human? In a cow with 26 chromosomes?

•How many phenotypes can be produced from the following cross? AABbcc x AaBBCC

Mendelian Genetics, Review9 March 2010

Our Goals

•80% Class Averages Class Celebrations for every block that makes

it•Each individual will score at least one

grade higher on the unit exam than their mock quiz▫High fliers list for everyone who scores

80% or higher

Molecular Genetics

•Molecular Genetics is the study of how DNA is changed into workable substances that control our bodies

Mendelian Genetics

•Mendelian Genetics is the study of how we inherit DNA from our parents

Vocab

•Genotype▫ A genotype is how we write combination of

alleles from each parent Aa, AA, aa

•Phenotype▫ The physical traits that the genotype

produces Long fingers, brown hair, widow’s peak

Vocab

•Dominant▫ Dominant traits only require one allele to

present▫ They are able to hide the recessive allele

AA, Aa

•Recessive▫ Recessive traits require two alleles to be

present

Vocab

•Homozygous▫ Homozygous individuals receive the same

allele from both parents AA, aa, BB, bb, CC, cc

•Heterozygous▫ Homozygous individuals receive a different

allele from each parent Aa, Bb, Cc

CFU

Calculating Probability

•For genotype,▫ Determine which individuals have a

dominant allele or a recessive allele For the dominant individuals, determine if

they are homozygous or heterozygous

•Write the ratio as follows:• Homozygous Dominant : Heterozygous : Homozygous

Recessive

Calculating Probability

•For phenotype,▫ Determine which individuals have a

dominant allele or a recessive allele

•Write the ratio as follows:•Dominant phenotype : Recessive

phenotype

CFU

Determining genotype from offspring•Steps:

▫ Determine known phenotypes and genotypes

▫ Establish ratio of dominant to recessive phenotypes

▫ Fill in punnett with known genotypes▫ Complete the rest of the punnett square by

filling in the missing pieces

Determining genotype from offspring•Multiple crosses between the same male

black hamster and female brown hamster produce a total of 12 brown and 14 black hamsters. If black is dominant and brown is recessive, what are the most likely genotypes of the parents?

•Determine known phenotypes and genotypes

Determining genotype from offspring•Multiple crosses between the same male

black hamster and female brown hamster produce a total of 12 brown and 14 black hamsters. If black is dominant and brown is recessive, what are the most likely genotypes of the parents?

•Establish ratio of dominant to recessive

Determining genotype from offspring•Multiple crosses between the same male

black hamster and female brown hamster produce a total of 12 brown and 14 black hamsters. If black is dominant and brown is recessive, what are the most likely genotypes of the parents?

•Fill in punnett with known genotypes

Determining genotype from offspring•Multiple crosses between the same male

black hamster and female brown hamster produce a total of 12 brown and 14 black hamsters. If black is dominant and brown is recessive, what are the most likely genotypes of the parents?

•Fill in the rest of the punnett square