THURSDAY JANUARY 22

Today we will go over the article that I had you read after your test last Friday. Then, we will take a pre-assessment on the upcoming unit, Genetics. After that we will begin the notes on Genetics and begin filling out our vocabulary sheets that I mentioned yesterday.

TODAY I WILL:Be able to define the terms homozygous and heterozygous.Be able to differentiate between dominate and recessive genes.Be able to tell the difference between genotype and phenotype.

FRIDAY JANUARY 23

Good afternoon and happy Friday to you! Today we will review some of what we went over yesterday and then continue on to learn about Mendel. I have a Crash Course video that deals with what we have discussed so far. Then, I want to give you some time today to work on your vocabulary sheets.

TODAY I WILL:Be able to discuss Mendel and how he impacted the field of genetics.Be able to differentiate between homozygous and heterozygous, and genotype and phenotype.

MONDAY JANUARY 26Today we will review some of things that we have learned so far in our genetics unit. We will go over the difference between gene and allele, dominant and recessive alleles, genotype and phenotype, and homozygous and heterozygous genotypes. After that, I would like to give you time to work on your vocabulary sheets because we will be having a QUIZ over those terms on FRIDAY.

TODAY I WILL:Be able to tell the difference between homozygous dominant and homozygous recessive genotypes.Be able to differentiate between dominant and recessive alleles.

TUESDAY JANUARY 27

Good afternoon and hello to you all! Today we will be reviewing a little bit more, specifically the difference between a gene and an allele. Then we will continue on with our notes and start

“Fun with ‘Pun’nett Squares!” TODAY I WILL:

Be able to differentiate between a gene and an allele.Be able to predict different genotypes using Punnett squares.Be able to read, fill out, and understand a Punnett square for a monohybrid cross.

WEDNESDAY JANUARY 28

Today we will finish up our Punnett square practice sheets in class. Then we will have time to complete our vocabulary sheet in preparation for the QUIZ on Friday. Do not forget, if you want to take the retake on Mitosis and Meiosis, I will be available after school today.

TODAY I WILL:Be able to properly fill out a Punnett square and be able to decipher it’s meaning.Predict the probability of genotypes percentages based on information from a Punnett square.

THURSDAY JANUARY 29 Today will be a

SILENT STUDY HALL DAY.I have for you a new practice sheet on Punnett squares that I want you to complete. When you are finished with that, come and show me so that I can check it and make sure that you are understanding the concept. Then you may work on your vocabulary sheet in preparation for tomorrows quiz. There will be NO TALKING , NO SLEEPING and you will work on the tasks that I have asked you to do before working on anything else.

NO EXCEPTIONS. NO EXCUSES.

FRIDAY JANUARY 30

Today is your QUIZ on vocabulary for our Genetics Unit. Once you are finished with your quiz, turn it in up front and grab the sheets for our Monster Making activity today. Also, pick up a copy of the homework that will be due MONDAY, FEBRUARY 2.

TODAY I WILL:Be able to create an organism by going from alleles to genotypes to phenotypes.Be able to correctly identify the different terms for the genetics unit.

MONDAY FEBRUARY 2

Today we will finish up our Monster Makers. Each person will fill out the genotypes and phenotypes for each trait and each person will draw out their monster. Then, I will ask for some volunteers to share their monster with the class. Then, if there is time, will watch a video on Gregor Mendel.TODAY I WILL:Be able to differentiate between genotype and phenotype.Understand and read the information from a Punnett square.

BELLWORK

Having hitchhiker’s thumb (H) is dominant to not having hitchhiker’s thumb (h). A heterozygous male is crossed with a homozygous recessive female.

F1 Generation:

Phenotypes Probabilities: Genotype Probabilities:

Hitchhiker’s thumb:____________ HH:_________

No hitchhiker’s thumb:__________ Hh:_________

hh:_________

TUESDAY FEBRUARY 3

Please take out your notes because today, we will learn about Incomplete Dominance and how it differs from what we have been talking about so far. We will take some notes and then we will have a practice sheet that we will do together in class.

TODAY I WILL:Be able to differentiate between complete and incomplete dominance.Be able to use a Punnett square to be able to extract information about incomplete dominant alleles.

BELLWORK

Being able to roll your tongue (T) is dominant to not being able to (t). A heterozygous male is crossed with a homozygous dominant female. F1 Generation:Phenotypes Probabilities: Genotype Probabilities:Tongue Rolling:____________ TT:_________ No tongue rolling:__________ Tt:_________

tt:_________ 

THURSDAY FEBRUARY 5

Today we will explore another type of inheritance, codominance. We will learn about this new inheritance pattern and how it differs from the other two that we have already explored. Then we will do some sample problems to better understand this concept.TODAY I WILL:Be able to differentiate between complete, incomplete, and codominance.Using a Punnett square be able to predict the genotypes and phenotypes of an organisms showing codominacne

BELLWORK

Skin color in aliens is incompletely dominate. Blue and yellow skin color are the homozygous traits and green is the heterozygous trait. If a green and a blue alien mated, what would be the genotypic and phenotypic ratios of the F1 generation be?

FOR EACH FLOWER TELL ME…

1. Whether it is Homozygous or heterozygous. If it is Homozygous, is it dominant or recessive?

2. What it’s Phenotype is.

3. What it’s Genotype is.

UNIT 7: GENETICS

CHAPTER 6, SECTIONS 3, 4, & 5CHAPTER 7

TOPIC 1: TERMINOLOGY FOR GENETICS

TERMS

Gene: a segment of DNA with coded information for a particular trait or characteristic.

Because animals are diploid (i.e., chromosomes in homologous pairs), there are 2 genes for each trait…one inherited from each parent.

Gene

TERMS

Allele: Actual DNA “letters” or N-base codes found in the chromosome

One allele is inherited from each parent for each genetic trait Ex: Gene = repair enzyme; Alleles

= broken vs normal

purple white

P p

TERMS

Gene Notation: letters are used to represent traits Rule: 1 letter for each trait

Dominant allele: alleles which hide or mask the information carried by recessive alleles. Dominant allele is expressed when 2

different alleles are present

Notation = capital letters› Ex: R = normal repair enzyme allele

TERMS

Recessive allele: alleles which are only expressed or observed when NOT paired with a dominant allele Recessive alleles are only expressed when

there are 2 copies present

Notation = lowercase letters

› Ex: r = broken repair enzyme allele

TERMS

Genotype: the 2 alleles inherited for each genetic trait the actual genetic info.› Homozygous: 2 copies of the same allele

for a trait. Ex: RR or rr› Heterozygous: 2 different alleles for a

trait Ex: Rr Phenotype: physical appearance of

the expressed trait which can be seen. › Ex: have the disease or are normal and

symptom free? (i.e., sick or healthy?)

LET’S REVIEW

Homozygous or heterozygous? Homozygous

LET’S REVIEW

Homozygous or heterozygous? heterozygous

LET’S REVIEW

What is this flower’s genotype? Ff (heterozygous)

LET’S REVIEW

What is this flower’s phenotype? purple

LET’S REVIEW

What is this flower’s phenotype?. white

LET’S REVIEW

What is this flower’s genotype? ff

LET’S REVIEW

Is this flower homozygous or heterozygous? heterozygous

TOPIC 2: CRACKING THE CODE OF HEREDITY

GeneticsThe study of heredity, how traits are passed from

parent to offspring

x =

or

or

6.3: MENDEL & HEREDITY

Heredity was a mystery for a long time It was thought that parents’ traits

blended in the next generation…like red and white blend to make pink

Are there any traits that are NOT inherited this way?

GREGOR MENDEL

Austrian monk “The Father of Genetics” The first person to start unraveling the

mystery of heredity in the 1800s

Modern genetics began with Gregor Mendel’s experiments with pea plants

EXPERIMENTAL GENETICS BEGAN IN AN ABBEY GARDEN

Figure 9.2A, B

Stamen

Carpel

MENDEL’S EXPERIMENTS

Mendel crossed pea plants that differed in certain characteristics and traced the traits from generation to generation

Mendel studied seven pea traits for several years and discovered they were each inherited in a similar math pattern.• He hypothesized that

these traits were shaped by alternative forms of genes --the units that determine heredity

FLOWER COLOR

FLOWER POSITION

SEED COLOR

SEED SHAPE

POD SHAPE

POD COLOR

STEM LENGTH

Purple White

Axial Terminal

Yellow Green

Round Wrinkled

Inflated Constricted

Green Yellow

Tall Dwarf

Parents have two alleles for every trait, but only give one allele to a gamete (sex cell)

In the offspring, one allele comes from each parent Ex. The F1 purple

flower received 1 allele for purple and 1 for white from each parent

MENDEL’S LAW OF SEGREGATION DESCRIBES THE INHERITANCE OF A SINGLE TRAIT

P GENERATION(true-breedingparents)

F1 generation

F2

generation

Purple flowers White flowers

All plants have purple flowers

Fertilization among F1 plants(F1 x F1)

3/4 of plantshave purple flowers

1/4 of plantshave white flowers

• Mendel suggested that many traits have two opposite forms that are determined by dominant or recessive alleles (i.e., dominant purple hides recessive white)

• Why did the white color disappear in the F1 generation but reappear in the F2 generation?

• Only when two recessive alleles are inherited in the F2 generation will the recessive trait show (white = pp)

P GENERATION(true-breedingparents)

F1 generation

F2

generation

3/4 of plantshave purple flowers

1/4 of plantshave white flowers

Purple flowers White flowers

All plants have purple flowers

Fertilization among F1 plants(F1 x F1)

TOPIC 3: GENETIC CROSSES (ONE & TWO-TRAIT)

The inheritance of many human traits follows Mendel’s principles and the rules of probability

PUNNETT SQUARES Punnett square: a box like diagram used

to predict all possible genotypes that result from a cross

Punnett square Quick Tips: Define your dominant & recessive letter

symbols: make a key Write each parent’s genotype Fill in Mom’s egg and Dad’s sperm

varieties along the PS sides Complete the PS boxes to see all the

possible genetic cross outcomes or kids’ genotypes

LAYOUT OF PUNNETT SQUARES

Dad's Sperm varieties (Alleles)

Mom's Egg Varieties (alleles)

Symbol Key

Parent Genotypes

Kids’ Genotypes

PUNNETT SQUARES: ONE TRAIT CROSSESMONOHYBRID CROSSES

Example 1: Having freckles is dominant trait. What is the chance that a child will have freckles if DAD is homozygous for freckles and MOM does not have freckles? ______

Gene Notation Symbols

F = freckles f = no frecklesParent Genotypes:

MOM: ff DAD: FF

f f

F

F

Ff Ff

Ff Ff

4/4

ONE TRAIT CROSSES CONT…

Example 2: If two offspring from the F1 generation in Example 1 are crossed, what is the chance that a child will have freckles? ____

Gene Notation Symbols

F = freckles f = no frecklesParent Genotypes:

MOM: Ff DAD: Ff

F f

F

f

FF Ff

Ff ff

3/4

ONE TRAIT CROSSES CONT… Example 3: Widow’s peak is a

dominant trait. What is the chance that a child will have a straight hairline if DAD is heterozygous for widow’s peak and MOM has a straight hairline? _______Gene Notation

Symbols

H = widow’s peak h = straight hairlineParent Genotypes:

MOM: hh DAD: Hh

h h

H

h

Hh Hh

hh hh

2/4

PUNNETT SQUARES: TWO TRAIT CROSSESDIHYBRID CROSSES

Dihybrid crosses involve two genes (traits)—this means that four alleles are involved. Punnett squares for dihybrid crosses have

16 boxes instead of 4 Law of Independent assortment: allele

pairs separate independently of each other during gamete formation (meiosis) Different traits appear to be inherited

separately

TWO TRAIT CROSSES CONT…

Example 1: In pea plants, yellow color is dominant to green color, and round pods are dominant to wrinkled pods. If two parents are crossed who are both heterozygous for both traits, what is the phenotypic ratio of the F1 generation?Gene Notation

Symbols

Y = yellow color y = green color

R = round pods r = wrinkled pods

Parent Genotypes:

MOM: YyRr DAD: YyRr

TWO TRAIT CROSSES EXAMPLE 1 CONT… When you have a dihybrid cross

involving 4 alleles, above each column and row should have 2 alleles, one for each trait:

Mom: Y y R r 1st column: YR, 2nd: Yr, 3rd: yR, 4th: yr

Dad: YyRr 1st row: YR, 2nd: Yr, 3rd: yR, 4th: yr

TWO TRAIT CROSSES, EXAMPLE 1 CONT…

YR Yr yR yr

YR

Yr

yR

yr

YYRR YYRr YyRR YyRr

YYRr YYrr YyRr Yyrr

YyRR YyRr yyRR yyRr

YyRr Yyrr yyRr yyrr

TWO TRAIT CROSSES, EXAMPLE 1 CONT… The following genotypes result in yellow

round pea pods (phenotype): YYRR, YYRr, YyRR, YyRr

The following genotypes result in yellow, wrinkled pea pods (phenotype): YYrr, Yyrr

The following genotypes result in green, round pea pods (phenotype): yyRR, yyRr

The following genotypes result in green, wrinkled pea pods (phenotype): yyrr

TWO TRAIT CROSSES, EXAMPLE 1 CONT… To get the phenotypic ratio for the F1

generation, count how many of each phenotype there is

Therefore, the phenotypic ratio is: 9:3:3:1

9 yellow, round: 3 yellow, wrinkled: 3 green, round: 1 green, wrinkled

TWO TRAIT CROSSES CONT…

Example 2: If you take two offspring from the F1 generation: YYRr & Yyrr, what will the F2 phenotypic and genotypic ratios be?

Mom’s alleles: YR, Yr, YR, Yr Dad’s alleles: Yr, Yr, yr, yr

Gene Notation Symbols

Y = yellow color y = green color

R = round pods r = wrinkled pods

Parent Genotypes:

MOM: YYRr DAD: Yyrr

TWO TRAIT CROSSES, EXAMPLE 2 CONT…

YR Yr YR Yr

Yr

Yr

yr

yr

YYRr YYrr YYRr YYrr

YYRr YYrr YYRr YYrr

YyRr Yyrr YyRr Yyrr

YyRr Yyrr YyRr Yyrr

TWO TRAIT CROSSES, EXAMPLE 2 CONT… F2 Genotype ratio:

4 YYRr: 4 YYrr: 4 YyRr: 4 Yyrr F2 Phenotype ratio:

8 yellow, round: 8 yellow, wrinkled

TOPIC 4: COMPLEX INHERITANCE PATTERNS

INCOMPLETE DOMINANCE, CODOMINANCE AND SEX-LINKED TRAITS

The inheritance of some traits is more complex than Mendel’s principles can explain

VARIATIONS ON MENDEL’S PRINCIPLES

The relationship of genotype to phenotype is rarely simple

Sometimes the 2 alleles for a trait BLEND together creating an intermediate phenotype = incomplete dominance

Neither allele is dominant

INCOMPLETE DOMINANCE RESULTS IN INTERMEDIATE PHENOTYPES

P GENERATION

F1 GENERATION

F2 GENERATION

RedRR

Gametes R r

Whiterr

PinkRr

R r

R R

r r

1/21/2

1/2

1/21/2

1/2 SpermEggs

PinkRr

PinkrR

Whiterr

RedRR

Figure 9.12A

INCOMPLETE DOMINANCE CONT…

Heterozygotes show an intermediate phenotype RR = red flowers rr = white flowers Rr = PINK flowers

make 50% less color

INCOMPLETE DOMINANCE CONT…true-breedingred flowers

RRHomozygous

Dominant

true-breeding white flowers

rrHomozygous

Recessive

X

100% Rr

100% pink flowers

F1generation(hybrids)

25%white

F2generation

25%red 1:2:1

RR:Rr:rr

P

self-pollinate50%pink

INCOMPLETE DOMINANCE CONT…

Example 1: In betta fish, green color is homozygous, steel blue is also homozygous, and the heterozygous trait is royal blue. What is the genotypic and phenotypic ratio of the F1 generation if a steel blue fish is crossed with a royal blue fish? Gene Notation

Symbols

BB = green color bb = steel blue color Bb = royal blue color

Parents’ genotypes

MOM = bb DAD = Bb

INCOMPLETE DOMINANCE, EXAMPLE 1 CONT…

b b

B

b

Bb Bb

bb bb

• F1 genotypic ratio: 2Bb : 2bb

• F1 phenotypic ratio:

2 steel blue: 2 royal blue

CODOMINANCE

Codominance is when both traits are fully and separately expressed Both alleles express themselves Example: blood type

AB blood type

Human ABO blood types are determined by 3 alleles in the human gene pool:

• The alleles for A and B blood types are codominant, and have the following symbols:

• The O allele is recessive =• This means that there are two dominant

alleles and one recessive allele, but if the two dominant alleles are together, then they are both expressed

MANY GENES HAVE MORE THAN TWO ALLELES IN THE POPULATION = MULTIPLE ALLELES

IA IB i

IA IB

i

BLOOD DONATION

BLOOD TYPE

genotype phenotype phenotype status

IA IA IA i type Atype A oligosaccharides on surface of RBC

__

IB IB IB i type Btype B oligosaccharides on surface of RBC

__

IA IB type ABboth type A & type B oligosaccharides on surface of RBC

universal recipient

i i type O no oligosaccharides on surface of RBC

universal donor

CODOMINANCE CONT…

Example 1: List all the possible blood genotypes and phenotypes and their ratios for children conceived from a male heterozygous for type A blood with a woman with homozygous type B blood.

Gene Notation

Symbols

IAIA or IAi= Type A blood IBIB or IBi= Type B blood IAIB = Type AB blood ii = Type O blood

Parents’ genotypes

MOM = IBIB

DAD = IAi

CODOMINANCE, EXAMPLE 1 CONT…

IB

IA

i

IAIB

IB i

IAIB

Genotypes fractions Phenotypes fractions

IB i 1/2 1/2

1/22/4 =1/2Type AB blood

Type B blood

IB

IAIB

IB i

A human female = A human male = A baby’s gender depends on whether

Dad’s sperm delivers a X or Y chromosome

So, should Henry the 8th have executed all of his wives for not giving him sons?

SEX CHROMOSOMES AND SEX-LINKED GENESChromosomes determine sex in many species

XX

XY

SEX CHROMOSOMES

autosomal

chromosomes

Sex chromosomes

GENES ON SEX CHROMOSOMES

Y chromosome SRY: sex-regulation gene

master gene for maleness & male hormones

X chromosome other traits beyond sex

determination

HUMAN X CHROMOSOME

Sex-linked traits have genes on the X chromosome more than 60 diseases traced to

genes on X chromosome, including: Hemophilia Duchenne muscular dystrophy color-blindness

SEX-LINKED TRAITS

All genes that are carried on the X chromosome are considered to be sex-linked In many organisms, the X chromosome

carries many genes unrelated to gender Fruit fly eye color is a sex-linked

characteristic

Most sex-linked human disorders are due to recessive alleles Examples: hemophilia, red-green color

blindness A male receives a single X-linked allele

from his mother, and will have the disorder, while a female has to receive the recessive X allele from both parents to be affected

CONNECTION: SEX-LINKED DISORDERS AFFECT MOSTLY MALES

A B

C D

E

F

Color blind testing

Color blind pictures

SEX-LINKED TRAITS CONT… Example 1: Color-blindness is a sex-linked

trait. Jim is not colorblind and neither is his wife, Mary. However, because Mary’s dad WAS colorblind, she is heterozygous for red-green colorblindness. What are the chances that a daughter will be colorblind? What about a son? What are the chances that a daughter will be a carrier?

Gene Notation Symbols

XBXB = female non-carrier XBXb = female carrier XbXb = female colorblind XBY = male normal XbY = male colorblind

Parents’ genotypes

MOM = XBXb

DAD = XBY

SEX-LINKED TRAITS, EXAMPLE 1 CONT…

XB Xb

XB

Y

XBXB XBXb

XBY XbY

F1 phenotypes:½ females will be normal, ½ females will be carriers, ½ males will be normal, ½ males will be colorblind

The chance of having a colorblind child is ¼.