FIND THE ANSWERS TO THE FOLLOWING QUESTIONS IN YOUR TEXTBOOK (PP. 277-280). WRITE THE ANSWERS IN YOUR LAB NOTEBOOK. YOU HAVE 20 MINUTES.

Who was Gregor Mendel? An Austrian Monk, the father of modern genetics

What organism did Mendel study? Pea Plants

What is genetics? The study of heredity (how traits are passed down)

List three traits that Mendel studied in his pea plants Seed and pea color, flower color, pod color, seed shape,

texture, stem length, flower position, etc. Define allele What is the law of segregation? What is the law of independent assortment?

INTRO TO GENETICS – MENDEL’S PEAS

INTRO TO GENETICS – MENDEL’S PEAS

different forms of a trait – called alleles

Dominant

“stronger” – will mask the other form of the trait if it is present

Written as capital letters – “A, B, C, D, etc.”

Recessive

“weaker” – will only be visible if the dominant form is absent

Written as lower case letters – “a, b, c, d, etc.”

INTRO TO GENETICS

Homozygous – Two of the same type of allele (two dominant or two recessive)

AA, bb, etc…

Heterozygous – One dominant and one recessive allele.

Aa, Bb, etc…

WHICH WILL BE EXPRESSED – DOMINANT OR RECESSIVE?

AA

WHICH WILL BE EXPRESSED – DOMINANT OR RECESSIVE?

RR

WHICH WILL BE EXPRESSED – DOMINANT OR RECESSIVE?

Bb

WHICH WILL BE EXPRESSED – DOMINANT OR RECESSIVE?

dd

WHICH WILL BE EXPRESSED – DOMINANT OR RECESSIVE?

Cc

WHICH WILL BE EXPRESSED – DOMINANT OR RECESSIVE?

ff

TRAITS FOUR CORNERS

Farsightedness Curly Hair Widow’s Peak Dimples Roll Tongue Straight Thumb

Nearsightedness Straight Hair Straight Hairline No Dimples Can’t Roll Tongue Hitchhiker Thumb

DNA

Jeannie has straight hair, but both her parents have curly hair. Is straight hair dominant or recessive? Why?

GENOTYPE VS PHENOTYPE Genotype – the particular alleles an

organism has

Phenotype – the visible expression of the genotype

FFBb

HOW GENES ARE INHERITED Law of segregation – the two alleles

for each trait separate during meiosis.Ex: If the parent is Aa, this will

separate into A and a during meiosis. Law of independent assortment –

alleles for each trait separate independently of other traits.Ex: Just because a gamete (sperm or

egg) gets the dominant allele for seed color does not mean it will also get the dominant allele for seed shape. These two allele sets do not affect each other

HOW GENES ARE INHERITED Punnett Squares

A way to predict the possible genotypes of offspring from the genotypes of the parents

Gives you a ratio of possibilitiesCan do one allele pair (monohybrid), two

allele pairs (dihybrid) or even more in a single square

PUNNETT SQUARE PRACTICE Perform the following monohybrid

crosses: AA x AA Bb X BB Cc x Cc Dd x dd ee x ee

Perform the following dihybrid crosses: AABb x Aabb AABB x aabb AaBb x AaBb aaBb x AABb Aabb x AABB

DNA

What is an allele? Give an example of a homozygous and a heterozygous trait.

PEDIGREES

DNA

Look at the pedigree to the right. Those in red are color blind. Do you notice anything strange about who is color blind and who isn’t? What?

Complex Inheritance

Split into five groups.

You will each be assigned an article to read about a special pattern of inheriting alleles. You will be presenting the information in the article to the rest of the class.

You will have ten minutes to read the article and decide who is saying what. EVERYONE must speak!

Each group will have five minutes to present.