Probability of Inheritance Lesson 1

Probability of Inheritance Lesson 1 Mrs. Anna Ward Seventh Grade Science Ridge RoadMiddle School

Do Now!!! Please write each of the following statements. Use the following word bank to complete each sentence: • We note dominant alleles by using _________________. • We note recessive alleles by using _________________. • The _____________ are the traits that can be observed or seen. • The _____________ are the actual genetic traits that an organism has.

Announcements • Welcome Back! • Progress Reports

Agenda for today… • Review vocabulary from Genetics • Phenotype, Genotype, Dominant, and Recessive • Check for Understanding • Add two new vocabulary terms • Homozygous • Heterozygous • Check for Understanding • Create Vocab Comparison Cards for our Genetics Terms • Attach into Science Notebook

Phenotype/Genotype REVIEW • Phenotype: The characteristics you can observe/see or the organism has • EXAMPLE: My phenotype is Brown Hair. • Genotype: The actual genetic make-up of the organism • EXAMPLE: My genotype is Bb.

Check for understanding… • Which of the following is a genotype? • Brown Hair • Bb • Green Eyes • Huntington’s Disease • Xx • White Flowers • Curly Hair • cc Gg

Which of the following is a phenotype? • Blue Eyes • ff • Tall Plant • Gg • Wrinkled Peas • Dark Skin • Aa • RR • Attached Earlobes

Dominant & Recessive • Traits can be either DOMINANT or RECESSIVE. • DOMINANT TRAITS ALWAYS COVER UP RECESSIVE TRAITS. • DOMINANT = Big Letter (B) • RECESSIVE = Little Letter (b)

Practice • Mark which of the following are dominant: • D • d • F • f • r • G • g • y DOMINANT RECESSIVE DOMINANT RECESSIVE RECESSIVE DOMINANT RECESSIVE RECESSIVE

So, to practice…. Consider the if a person can have the Alleles… B—Brown Hair or b—Blonde Hair What are the possible Genotypes and Phenotype… • BB – 2 DOMINANT Alleles • Phenotype--BROWN HAIR • Bb – 1 DOMINANT Allele & 1 RECESSIVE Allele • Phenotype--BROWN HAIR • Bb – 2 RECESSIVE Alleles • Phenotype--BLONDE HAIR • Because blonde is recessive, you can not have any dominant “B” traits to mask the trait

Your Turn… • There are TWO possible alleles for seed shape in pea plants, WRINKLED or ROUND. • Round Peas are Dominant -- W • Wrinkled peas are recessive – w • If a pea plant has the following genotype, would it have round or wrinkled peas? • WW? • Ww? • ww? ROUND ROUND WRINKLED

One more try… • In cats, the allele for LONG tails (L) is dominant over the allele for SHORT tails (l). What would be the phenotype for the following genotypes? • LL? • Ll? • ll? LONG TAIL LONG TAIL SHORT TAIL

Homozygous Means…. • Homozygous means that the alleles in the genotype are the same, either both dominant (LARGE letters) or recessive (SMALL letters). • Examples: • RR—HOMOZYGOUS DOMINANT • rr—HOMOZYGOUS RECESSIVE • AA—HOMOZYGOUS DOMINANT • aa—HOMOZYGOUS RECESSIVE

Heterozygous means… • Heterozygousmeans that the alleles in the genotype are different, with both a dominant &recessive allele. • Examples: • Rr—HETEROZYGOUS • Aa—HETEROZYGOUS • Bb—HETEROZYGOUS

Check for Understanding… • In your notebook, write down whether each of the following is Homozygous (HO) or Heterozygous (HE). • AA • Ff • rr • Gg • HH • Bb HO HE HO HE HO HE

Vocabulary Comparison Cards

After you have attached the Comparison Cards, Complete the Exit Ticket: 1. In a Goddess Flower Plant, White Flowers (P) are dominant to purple flowers (p). What would the phenotype be if the plant had the following genotypes? • Pp? • pp? • PP? 2. How do we write a heterozygous genotype? 3. Would a heterozygous genotype show characteristics of the recessive or dominant allele?

Probability of Inheritance Lesson 1