Bell Work Who is Gregor Mendel and what

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

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: