OBJECTIVE: SWBAT define key terms used in genetics IOT explain the process of biological inheritance QUESTION: How do we know which genes we will inherit from our parents, and which genes will show up in our bodies? - For example, if your mother has blue eyes, and your father has brown eyes, how do you know what color eyes you will have?

Think for a second about the most crazy thing you have ever seen…

could be possible… Imagine in the future when something like THIS …

The future is now…

How did the scientists do it?

Intro. To Genetics

GENETICS the study of how traits are passed from one generation to the next

Gregor Mendel (Father of Genetics)  A scientist who studied genetics  He did his studies using normal garden peas  Developed the laws of inheritance (with no knowledge of chromosomes or genes)

What He Studied Mendel looked at traits of the pea plants – A trait is a characteristic – Examples: seed color, height of the plant…

What are some traits of this person?

What Mendel Wanted to Know… He wanted to see if you crossed 2 plants with different traits, what would the offspring look like Mendel was successful because pea plants were: Pure breeding (7 contrasting traits) Self Fertilizing Have large numbers of offspring

From his experiments he concluded Inheritance is determined by factors that are passed from one generation to the next

GENE: the factors that control traits (found in the DNA) example: color of a flower

ALLELES Each gene comes in different forms called alleles Each parent gives one allele to the offspring Example: so the gene that controls flower color may come in two alleles: purple and white.

CFUs 1. Genes are found where? 2. What are the different forms of a gene called? 3. What would be an example of a gene and its alleles? 4. Where do the alleles come from? DNA ALLELES Gene- Height, Alleles- tall and short One from each parent!

Which one do you look like? Genes can either be dominant or recessive

Dominant Genes If a dominant gene is present, the trait is ALWAYS expressed  Dominant alleles are written with a capital letter  Example: Tall pea plant = dominant =T

Recessive Genes Recessive genes are ONLY expressed if there are 2 copies of the recessive allele present – Recessive alleles are written with a lower case letter – Example: Short pea plant = recessive = t

Example… The gene for brown hair is dominant so….an individual just needs one B for the trait to be expressed – BB = brown hair – Bb = brown hair

Examples… The gene for blond hair is recessive and represented by a lower case b. – bb = blond hair

You can’t express everything! Vocabulary – Genotype: Genetic makeup – Examples: TT, Tt, tt – Phenotype: Physical characteristics – Examples: Tall, short, blue, long

Heterozygous vs. Homozygous Vocabulary: – Heterozygous: copies of different genes Hetero - different Example: Tt – Homozygous: copies of the same genes Homo - same Example: TT or tt

Let’s Practice 1.Circle one: “PP” is considered (homozygous/heterozygous) 1.Circle one: “Pp is considered (homozygous/heterozygous) 1.Circle one: “pp” is considered (homozygous dominant/homozygous recessive)

Let’s Practice For each genotype, determine the phenotype 1.Tall (T) plant is dominant over short (t) TT ______________ Tt ______________ tt _______________ TALL SHORT

Let’s Practice For each phenotype, list the genotype 1.White flowers are dominant to purple flowers White flowers _________ Purple flowers _________ Ww ww WW

CLASSWORK Complete the Genetics Practice! Be prepared to share Afterwards….we will have an EXIT TICKET! 10 min

Exit Ticket Write your answers on a separate sheet of paper. Be prepared to share. Why are there two alleles for each trait? Give an example of a phenotype. Give an example of a homozygous dominant genotype. Which type of gene is never expressed unless there are two copies of the allele? Who is considered the father of genetics?

How can we determine what the offspring are going to be?

PUNNETT SQUARES chart showing the possible combination of alleles in a cross

THE PARENTS GENOTYPES MOM = Bb (heterozygous brown hair) DAD = bb (homozygous blond hair) PHENOTYPES MOM = brown hair DAD = blond hair

bb b BBbBb bb bb

THE OFFSPRING Tt (heterozygous) tt (homozygous recessive) GENOTYPES

THE OFFSPRING 2 Bb (brown hair) 2 bb (blond hair) PHENOTYPES

You Try! PARENTS (T represents tall) GENOTYPES DAD = Tt (heterozygous) MOM = Tt (heterozygous) PHENOTYPES DAD =Tall MOM = Tall

PUNNETT SQUARES

THE OFFSPRING TT (homozygous dominant) Tt (heterozygous) tt (homozygous recessive) GENOTYPES

THE OFFSPRING TT (tall) Tt (tall) tt (short) PHENOTYPES