Bell Work Who is Gregor Mendel and what did he do?

Genetics with Punnett Squares Biology – Lecture 47 Genetics with Punnett Squares

Genetics Vocabulary

Allele – different versions of the same gene Because they are the same gene, they are given the same letter. Example – height can either be tall or short

Genotype - the set of alleles for a given organism Phenotype - the observable traits of the organism

Homozygous - Diploid organisms with two copies of the same allele of a given gene. Both alleles will be capital letters or lower case letters. Heterozygous - Diploid organisms with two different alleles of a given gene. One allele will be capital, one allele will be lowercase.

Dominant allele – The allele in a heterozygous set of alleles that has dominant qualities in the phenotype. (capital letter) Recessive allele – the allele in a heterozygous set of allele that has receding qualities and are not observed in the phenotype. (lower-case letter)

Incomplete dominance - expressing an intermediate phenotype Co-dominance - expressing both alleles at once

Punnett Square - a diagram that is used to predict an outcome of a particular cross or breeding experiment.

Punnett Square Example In rabbits, black fur is dominant over white fur. Show the cross of a heterozygous black male with a homozygous white female. Phenotype: Genotype:

Punnett Square Example In humans, free-ear lobes are dominant to attached. Two parented that are both heterozygous free are expecting a child. What are the chances that the child will have free ear lobes of attached? Phenotype: Genotype:

Punnett Square Practice Wrinkled seed are recessive to smooth seeds. Show a plant that always produces wrinkled seeds crossed with a heterozygous smooth seeds producing plant. Phenotype: Genotype:

Punnett Square Practice Wrinkled seed are recessive to smooth seeds. Show a heterozygous smooth plant crossed with another heterozygous smooth seed producing plant. Phenotype: Genotype:

Punnett Square Practice Blue eyes are dominant to red eyes in rabbits. Show a heterozygous blue-eyed rabbit crossed with a red-eyed rabbit. Phenotype: Genotype:

Punnett Square Practice In fruit flies, red eyes are dominant over white eyes. Show a cross between two white-eye fruit flies. Phenotype: Genotype:

Punnett Square Practice Curly hair is recessive, and straight hair is dominant. A woman with curly hair marries a man who is homozygous dominant for straight hair. Predict the outcomes for their children. Phenotype: Genotype:

Punnett Square Practice Black hair is homozygous dominant. Brown hair is heterozygous. Blonde hair is homozygous recessive. (This is an example of incomplete dominance.) A woman with brown hair marries a man with brown hair. What are the possible outcomes for their kids? Phenotype: Genotype:

Punnett Square Practice Freckles are recessive. No freckles are dominant. Mom= heterozygous Dad=homozygous recessive. What are the possible outcomes for kids? Phenotype: Genotype:

Pop Quiz

Pop Quiz - Punnett Square Tall is dominant over short in pea plants. Show the cross of a homozygous short plant is crossed with a homozygous tall plant. Phenotype: Genotype: