GeneticsGenetics

GeneticsGenetics

Bell: What is Genetics?

Study of heredity

passing of traits from parents to offspring

Traits- Visible characteristics

Gregor MendelGregor Mendel

Watch video clips- DVD and “From the Gardent to the Genome” YouTUBE- click for link

“Father of Genetics”

Austrian Monk

Conducted experiments with peas

Used numbers in the study of biology

Gregor MendelGregor MendelExperimented with

Self-pollination - fertilization within itself

Creation of pure-breed or true-breed

offspring identical to parents

Cross-pollination - fertilization of one by another

Offspring from both parents

Gregor MendelGregor MendelHow many experiments were needed to determine conclusive results?

Heads/Tails Activity

Round x Wrinkled = 7324 offspringYellow x Green = 8023 offspringAxial x Terminal = 858 offspringPurple x White = 929 offspringInflated x Constricted = 1181 offspringGreen x Yellow = 580 offspringTall x Dwarf = 1064 offspring

Mendel’s First Mendel’s First Experiment- Experiment-

Terminology and Terminology and CrossesCrossesParental Generation - P

- Purebreds for each parent

1st Filial - F1 (first generation)

offspring of cross (children)

created hybrid - cross between 2 parents

2nd Filial - F2 (second generation)

Grandchildren

Mendel’s ConclusionsMendel’s ConclusionsI. Traits are determined by a “factor”

Now termed GENES

Different forms of a gene are called ALLELE

II. Each “factor” is inherited separately

III. Each trait is determined by one of the “factors” inherited from the parents

Principle of Dominance -

Dominant masks the expression of the recessive

Bellringer - Genetics Bellringer - Genetics Day 2Day 2

What will be the fur color of the offspring of Benjamin Bear and Elizabeth Bear?

Genetics TerminologyGenetics Terminology

Purebred or True-breed

Dominant

Recessive

Genotype

Phenotype

Homozygous

Heterozygous

Practice with REEBOPSPractice with REEBOPSHow many show the dominant phenotype for body segments?

How many show the recessive eye number?

What is the genotype of those showing the recessive eye number?

What is the genotype of those showing the dominant phenotype for eye number ?

Are there any traits that are not dominant or recessive?

*Which of the traits shown are heterozygous?

4

1

ee

EE or Ee

Hump #, Nose Color, Antennae # Orange Nose, 2 antennae, 2 humps

Teddy Bear GeneticsTeddy Bear Genetics

Law of Segregation = 2 forms of a gene/ allele are separated during meiosis

(one to each gamete)

Complete the Teddy Bear Genetics

ProbabilityProbabilityLikelihood that an event will happen

Ex) coin toss

1 coin flip = 1/2 chance or 50%

Heads 3 times in a row = 1/2 x 1/2 x 1/2 = 1/8

1/2 chance for each event (flip)

Principles of Probablility can be used to predict genetic outcomes

Genetics and Genetics and ProbabilityProbability

Ability to roll tongue = dominant trait

Can you determine your genotype?

With a partner:

John is heterozygous for tongue rolling and Nancy cannot roll her tongue. What is the chance that they will have children that cannot roll their tongue?

How did you figure it out?

Genetics and Genetics and ProbabilityProbability

Punnett Square - tool used to predict genetic combinations

Tongue Rolling problem with punnett square

Closure problem: George and wife are both heterozygous for widow’s peak. What percentage of their children will have a Widow’s peak?

HW: Bikini Bottom Genetics

Genetics and Genetics and Probability Probability

Day 3Day 3Bellringer: Mom and Dad both have free earlobes. Junior also has free earlobes. His sister has attached earlobes. What are Mom and Dad’s genotypes in relation to earlobes? What is the chance that they will have another child with attached earlobes?

Check Bikini Bottom Genetics

Classwork: Genetics Worksheet

Genetic CrossesGenetic Crosses

Test Cross: used to determine genotype of dominant phenotype

Cross an “unknown” dominant with a recessive

Why?

Genetic Crosses - 2 Genetic Crosses - 2 traitstraits

Principle of Independent Assortment -

genes segregate independently during meiosis

cause of different genetic combinations in gametes

Dihybrid cross

both parents are hybrid for 2 traits

Genetic Crosses - 2 Genetic Crosses - 2 traitstraits

Dihybrid worksheet practice

Mendel’s peas activity

Dihybrid Crosses

Beyond Dominant and Beyond Dominant and RecessiveRecessive

Incomplete Dominance -

neither allele is dominant over the other

Purebreds phenotypes are 2 extremes

Hybrid phenotype is in the middle

Incomplete DominanceIncomplete Dominance4 o’clock Flowers4 o’clock Flowers

X

Beyond Dominant and Beyond Dominant and RecessiveRecessive

Codominance

Both alleles are dominant

Hybrid shows both traits

Codominance-Codominance-Roan CattleRoan Cattle

Bell: Day 5Bell: Day 5How are codominant and incomplete dominant alleles different than dominant and recessive alleles?

AGENDA

Incomplete Dominance Practice

Multiple Alleles

Blood Typing Lab

Blood Type Problems

Multiple AllelesMultiple Alleles

Humans have ______ blood types

Alleles:

Type

A =

B=

AB =

O=

Human Heredity: Day Human Heredity: Day 66

Bell: What is the genotype of the possible children if a heterozygote for Widow’s peak marries a homozygous recessive (straight hairline)?

What is/are the possible phenotype(s)?

AGENDA1. Independent Projects2. Blood Typing3. Pedigrees4. Sex-linked traits

*Quiz NEXT time*

Human HeredityHuman HeredityHuman Chromosomes

Human cell =

46 chromosomes (23 pairs)

1 set from Mom (egg) : 1 set from Dad (sperm)

2 of those are known as sex chromosome

Female = XX

Male = XY

Remaining 44 chromosomes = autosome

PedigreePedigree

Chart that shows the relationships within a family

Often used to determine the mode of inheritance

Pedigree (cont.)Pedigree (cont.)Female =

Male =

Affected Female =

Affected Male =

If a heterozygote is known then half of the shape is shaded

Pedigree Practice Worksheet

Pedigree Practice: Pedigree Practice: Autosomal Dominant?Autosomal Dominant?

Draw each pedigree

Assume that the affected trait is dominant. Write the genotypes beside each recessive individual

Is it possible for this trait to be autosomal dominant? -Circle if possible or X if not possible

A. B. C.

• Can two affected individuals have unaffected children?

Pedigree PracticePedigree PracticeAutosomal Recessive?Autosomal Recessive?

Assume the trait is recessive.

Draw the pedigree and write the genotype beside each person.

Is it possible for the trait to be recessive? - Circle if possible or X if not possible

If the trait is autosomal recessive, what can you conclude the children will be of two affected parents?

A. B. C.

Pedigree PracticePedigree Practice

Is the affected trait autosomal dominant or recessive? Why?

Carrier - Heterozygote that “carries” the affected allele, but does not express the allele (Allele remains hidden.)

** Who are the carriers?

Day 7 Day 7 Bell:

Fifty wavy-haired couples decide to form a commune, because they think wavy hair is cool. Each couple has two children. Out of the 100 children, how many of them should have “uncool” straight hair? (Of course, they will have to be excommunicated, along with their curly-haired siblings, once they reach adulthood.)

AGENDAQuizPedigreeSex-linked Traits

Sex-Linked GenesSex-Linked Genes

Pattern of inheritance is located on the X-chromosome or the Y- chromosome

Y is much smaller

Therefore, there are more X-linked disorders/traits

What numbers to you What numbers to you See?See?

Ex. ColorblindnessEx. Colorblindness

X-linked disorder

Most common in ?

Males (1/10)

Females (1/100)

Allele Definition -

Colorblind ProblemColorblind ProblemMarian’s father is colorblind. Marian herself has normal color vision. Marian and her husband, Martin, who is also colorblind, have just had their first child; a son they have named Mickey. (Write the genotypes of Marian and Martin.)

a. What is the probability that their son is colorblind?

b. If Martin were not colorblind, how would this affect the prediction about Mickey?

c. If Marian and Martin were to have a girl, who they would name Minnie, what is the probability that she would be colorblind?

X-linked BELLX-linked BELLHemophelia is a hereditary disease in which the blood does not clot. The allele for normal blood clotting is carried on the X chromosome.

1. A carrier female marries a hemophilic man. How many male children will have hemophilia? How many female children?

2. A normal woman whose father had hemophilia marries a normal man. What is the chance that their children will have hemophilia?

3. Todd is not colorblind. He is married to Ann whose father was red-green colorblind. Todd and Ann have 2 children, Ed is colorblind and lisa is not. What are the genotypes of Todd, Ann, Ed, and Lisa?

Pedigree PracticePedigree Practice

Draw the pedigree and write the genotypes beside each individual. Assume X-linked recessive.

Is it possible for it to be x-linked recessive?

What can you conclude about children whose mother is affected by an x-linked recessive trait?

CBA

X-linked ConclusionsX-linked Conclusions

What can you conclude about children if only the mother is affected by an X-linked recessive trait?

Why is it possible for females to be carriers of X-linked traits, but not males to be carriers?

BELL: PEDIGREEBELL: PEDIGREEOne last time!One last time!

BELL - Pedigree (one last time). Using the markers, solve the 1, 2, and 3 pedigrees

Erase when finished.

AGENDA1. Turn in Alcaptunuria Lab.2. Karyotype Internet Activity3. Karyotype notes4. Genetic Disorders/Disease Project

KaryotypeKaryotype

Organized profile of a human’s chromosomes

Chromosomes are paired by

centromere location

banding pattern

Size

Analyzing KaryotypesAnalyzing KaryotypesWhat can you tell by this karyotype?

Analyzing KaryotypesAnalyzing KaryotypesWhat can you tell by this karyotype?

Analyzing KaryotypesAnalyzing KaryotypesWhat can you tell by analyzing this karyotype?

Analyzing KaryotypesAnalyzing KaryotypesWhat can you tell by analyzing this karyotype?

Analyzing KaryotypesAnalyzing KaryotypesWhat can you tell by this karyotype?

Analyzing KaryotypesAnalyzing KaryotypesWhat can you tell by analyzing this karyotype?

Karyotype Analysis: Karyotype Analysis: Chromosomal Chromosomal

DisordersDisordersNondisjunction- occurs when either homologous chromosome fails to separate during meiosis

Results abnormal # of chromosomes in gametes

Trisomy = 1 extra homologous chromosome (3)

Polysomy = more than 1 extra

Monosomy = only 1 chromosome

Karyotype Analysis: Karyotype Analysis: Chromosomal Chromosomal

DisordersDisordersHigh frequency of Nondisjunction in humans

Results usually so devastating that it results in miscarriage

Only 3 trisomies that result in babies

Down’s syndrome - 21

Edward’s syndrome - 13

Patau Syndrome - 18

Nondisjunction: Nondisjunction: Sex Chromosomes Sex ChromosomesMonosomy (X only) = Turner’s Syndrome

Trisomy (XXY or XXXY) = Klinefelter’s Syndrome

Trisomy (XXX) - cannot be distinguished from normal females / no affect

When would the effect show up?

Chromosomal Chromosomal AlterationsAlterationsDeletion

Portion of Chromosome lost during cell division (genes lost = usually lethal)

Duplication

A fragment joins the chromosome and is then repeated

• Translocation

• A fragment is moved from one chromosome to another

Wrap-UpWrap-Up

Bell:Bell:

What is a karyotype?

How is a karyotype created?

Human Genetic Human Genetic Disorders AssignmentDisorders Assignment

Go to website for assignment

Human Human Disorders/DiseasesDisorders/Diseases

BELL:

What is a karyotype and how is it made?

Describe the 3 type of chromosomal alterations. Why do they affect an individual?

AGENDA•Human Disorders Project

(Presentations)•Genes and the environment

Perfect BabyPerfect Baby

AGENDA

Genetics Quiz #2

Perfect Baby Video

Discussion

Genes and the Environment

Human Genome and Human Genome and EthicsEthics

AGENDA

Human Genome - gene patenting

DNA databases

Designer Babies?

Video DiscussionVideo DiscussionWhat are some of the strange and unexpected discoveries made from analyzing the human genome?

Why is sequencing the human genome considered such an important and historic event

• Video - 7. Who Owns the Genome?

What effects might patenting genes have on current research efforts?

Do you think genes should be patented? Why or why not?

Group Work• With your group, read and answer the questions to the case study “Patenting Genes.” Elect a spokesperson to share your answers.

DNA DatabasesDNA Databases

13. DNA Databases - link

What are some ethical issues surrounding the creation of DNA databases?

What are some implications of creating DNA chips that would allow doctors to screen newborns for many diseases?

Case StudyCase Study

Newborn screening or Genetic Discrimination: read the case study with your group - appoint a spokesperson to share your answers

Should we create Should we create babies by design?babies by design?

Can we do it now? - link to 15. Genetic Modification

Should We Create Babies by Design? - Internet Activity

with a partner complete the web based activity through Mr. Lauver’s website (class assignments)

What is your position on “Babies by Design”? Why?