DO NOW: Quietly…….. Take a poll of how many of you have the following traits: - brown hair -blonde hair -red hair - black hair - blue/green eyes -brown eyes

G ENETICS

M AIN I DEA ………… Parent Traits Offsprings Traits

A LIEN ACTIVITY m.html

W HAT IS G ENETICS ??? Genetics is the scientific study of heredity. Heredity is what makes each species unique.

K EY V OCABULARY Dominant: inherited characteristic that appear in an organism Represented with capital letter. Ex: B, X, R

Recessive: inherited characteristics often masked Represented with lowercase letter. Ex: b, x, r K EY V OCABULARY

E XAMPLE : Brown Eyes: BBlue Eyes: b DominantRecessive

Phenotype: physical traits that appear in an individual as a result of its genetic make-up How to remember……. Ph enotype= Ph ysical Ex: brown eyes, blonde hair

Genotype: genetic Make Up of an individual How to remember…. GEN otype= GENE tic Ex: B- brown eyes b- blue eyes

having two identical alleles Ex: BB or bb  having two different alleles for a trait  Ex: Bb HomozygousHeterozygous

P HENOTYPE VS. G ENOTYPE bb Blue Eyes GenotypePhenotype A little girl has blue eyes

Allele different forms of a gene for a specific trait 2 for each trait

ALLELE Could code for a PURPLE flower Could code for a WHITE flower C HROMOSOME FOR F LOWER C OLOR

M AIN I DEA ………… Parent Traits Offsprings Traits

H ISTORY F ATHER OF G ENETICS : M ENDEL

G REGOR M ENDEL Austrian Monk Famous for his work with pea plants WHY????? They weren’t messy Rapid results Many generation He is known as the father of genetics

M ENDEL ’ S W ORK Mendel used true-breeding plants True Breeding: When bred with themselves they would produce identical offsprings. He studied 7 different traits in pea plants.

Trait: is a specific characteristic that can vary from one individual to another

M ORE ON M ENDEL ’ S W ORK Hybrids are offspring from parents with different traits. Genes are the chemical factors that determine a trait.

M ENDEL ’ S E XPERIMENTS : 3 P RINCIPLES 1. Principle of Dominance 2. Segregation 3. Independent Assortment

P RINCIPLE 1: T HE P RINCIPLE OF D OMINANCE States that some alleles are dominant and others are recessive. Dominant alleles are always expressed. Recessive alleles are only expressed if both alleles are recessive.

P RINCIPLE 2: S EGREGATION The two alleles for a trait separate HELP…… Segregate  means to separate Happens during meiosis form gametes (sex cells)

P RINCIPLE 3: I NDEPENDENT A SSORTMENT states that genes for different traits separate independently during the formation of gametes. EX: the color of the flower has nothing to do with the length They separate INDEPENDENTLY

S UMMARIZE M ENDEL ’ S P RINCIPLES The inheritance of biological characteristics are determined by genes. For two or more forms of a gene, dominance and recessive forms may exist (Principle #1). Most sexually reproductive organisms have two sets of genes that separate during gamete formation (Principle #2). Alleles segregate independently (Principle #3).

M AIN I DEA ………… Parent Traits Offsprings Traits

P ROBABILITY AND P UNNETT S QUARES

P ROBABILITY & G ENETICS Probability is the likelihood that an event will happen. The principle of probability can be used to predict the outcomes of genetic crosses.

P UNNETT S QUARES Diagram used to predict genetic crosses. REVIEW: Homozygous  individuals with identical alleles Heterozygous  individuals with different alleles are called Phenotype  physical characteristic Genotype  genetic makeup

H OW TO USE P UNNETT S QUARES …… 1. Choose a letter to represent the alleles in the cross. 2. Write the genotypes of the parents. 3. Enter the possible gamete at the top and side of the Punnett square. 4. Complete the Punnett square by writing the alleles from the gametes in the appropriate boxes. 5. Determine the phenotypes of the offspring. 6. Using the results of step 4. write down the genotypic and phenotypic ratios.

E XAMPLE P UNNETT S QUARE

W HAT IS THE PROBABILITY THAT TWO HETEROZYGOUS PURPLE FLOWERS WILL PRODUCE A WHITE FLOWER ? 1. Choose a letter to represent the alleles in the cross. 2. Write the genotypes of the parents. 3. Enter the possible gamete at the top and side of the Punnett square.

W HAT IS THE PROBABILITY THAT TWO HETEROZYGOUS PURPLE FLOWERS WILL PRODUCE A WHITE FLOWER ? 4. Complete the Punnett square by writing the alleles from the gametes in the appropriate boxes. 5. Determine the phenotypes of the offspring. 6. Using the results of step 4. write down the genotypic and phenotypic ratios

R EVIEW Q UIZ ON P ROBABLITY AND P UNNETT S QUARES ui2.htm

M AIN I DEA ………… Parent Traits Offsprings Traits

T EST C ROSSES

W HAT IS A T EST C ROSS ????? Test that is conducted to determine if the genotype of an organism HOMOZYGOUS DOMINANT for a trait HETEROZYGOUS for a trait

5 K EY P OINTS …… 1. The organism with the dominant trait is always crossed with an organism that is HOMOZYGOUS RECESSIVE 2. If ANY offspring shows the recessive trait than the unknown genotype is heterozygous. 1. Recessive trait seen  heterozygous 3. If ALL offspring have the dominant trait, the unknown is homozygous dominant. 1. Dominate trait  homozygous 4. Large numbers of offspring are needed for reliable results 5. Start by making a key and writing down what you know.

E XAMPLE : If fire breathing is dominant to not fire breathing in Gregorous Dragon, how can we determine if Mendelia is homozygous dominant or heterozygous?????

S O WHAT DO WE KNOW …………. Let’s say F= fire breathing f= can’t fire breathe. Set up a two different Punnett squares Both with a homozygous recessive  ff

Then as the other parent place a: FF in one Punnett square Ff is another Essentially, your two Punnett squares will have: Ff crossed with ff FF crossed with ff

I NTERPRETATION If all of the Gregorous dragon babies can firebreathe we can assume that Mendelia is HOMOZYGOUS DOMINANT If any of the babies DO NOT fire breathe than Mendelia is HETEROZYGOUS

D IFFERENT T YPES OF I NHERITANCE

D IHYBRID C ROSSES

Cross that involves two traits Gives 16 offsprings Example: Pea color and wrinkles

S TEPS F OR A D IHYBRID C ROSS 1. Make a key for the two traits that you are crossing 2. Write out the different genotypes of the parents 3. Figure out the possible gametes 1. similar to FOIL 2. there are four for each parent 3. each gamete must have one allele from each trait 4. Set up and Solve the Punnett Square

E XAMPLE P ROBLEM : A MOTHER IS HETEROZYGOUS BROWN HAIR AND BLUE EYES. T HE FATHER HAS BLONDE HAIR AND IS HETEROZYGOUS FOR BROWN EYES. W HAT ARE THE POSSIBLE GENOTYPES AND PHENOTYPES OF THEIR OFFSPRINGS ? Step 1 Make a key for the traits Brown Hair (B) vs Blonde Hair ( b) Brown Eyes (E) vs Blue eyes (e) Step 2 Genotypes of the parents Mother  Bbee Father  bbEe Step 3 Figure out the possible gamete Mother Gamete’s  Be, Be, be, be Father’s Gamete’s  bE, be, bE, be

S TEP 4  S ET UP AND S OLVE PUNNET S QUARE BeBebebe bE be bE be BbEe Bbee BbEe Bbee BbEe Bbee BbEe Bbee bbEe bbee bbEe bbee bbEe bbee bbEe bbee

C OUNT UP THE POSSIBLE GENOTYPES AND PHENOTYPES THAT YOU HAVE FROM YOUR PUNNETT SQUARE BbEe 4/16 Bbee 4/16 bbEe 4/16 bbee 4/16 Brown Hair; Brown eyes Brown Hair; Blue eyes Blonde Hair; Brown eyes Blonde Hair; Blue eyes GenotypesPhenotypes

S EX L INKED

sex is determined by the X and Y chromosomes. Females  XX Males  XY

S EX D ETERMINATION Sons: get their X chromosome from their mothers only. Get Their Y chromosome for their fathers Daughters: fathers must pass their X chromosomes

S EX L INKED T RAITS Traits found on the SEX chromosomes Genes that are found on the X chromosome follow a have a special pattern of inheritance: X linked traits are only passed to sons from the mother

Males are much more likely to be affected than females If trait is recessive, daughters have a second X chromosome so they can be heterozygous. Sons only have one X chromosome therefore more likely to express the trait

Females can be carriers and pass the trait onto their son. Example: Baldness Colorbindness

C OLORBLINDNESS

T RY THIS …… A woman is not colorblind but her husband is. Construct a punnett square to determine what is the chance that their children will be colorblind. What is the percentage of children with colorblindness?

A woman who is a carrier for hemophilia marries an unaffected male. What is the % chance that their children will be affected?

I NCOMPLETE D OMINANCE

when one trait is not completely dominant over another Results heterozygous form being blended together Example: Pink flower

S OLVING I NCOMPLETE D OMINANCE : Same as performing a regular monohybrid Punnett square Only difference heterozygous offspring will be mixture of two trait Ex: red + white = PINK

Example Problem: Black fur color are not completely dominant to white white fur color. The mother is a homozgygous for black fur color and the father is homozygous for white fur color. Perform a punnett square. B B b b Bb

C ODOMINANCE

Two different alleles are present and both are expressed Basically…….. Both alleles contribute to the phenotype. Example: Red cow X White Cow = Roan Cow Blood types

B LOOD T YPES : Red blood cells are coated with different protein markers. Person can have either A B A and B neither protein. Blood Types are: A B AB O

GenotypePhenotype IAIAIAIOIAIAIAIO A Blood I B I B I O B Blood IAIBIAIB AB Blood IOIOIOIO O Blood

E XAMPLE P ROBLEM #1 Melissa has type AB blood. Joe has type AB blood as well. If Melissa and Joe have a baby girl, what are the possible blood types the baby can have? HINT: Draw a Punnet Square!!!!!!

E XAMPLE P ROBLEM #2 David has blood type AB. Jessica has blood type O. They have a son that has blood type A? Since neither David nor Jessica have this blood type, was their a mistake in the hospital? HINT: Draw a Punnett Square to help!!!!!!!!!