Genetics I. Review Mitosis Asexual 1 cell Division Result: 2 cells Cells are Identical Cells are Diploid Review Vocab. Diploid – full set of.

GeneticsI. ReviewMitosis

Asexual 1 cell Division Result: 2 cells Cells are Identical Cells are Diploid

Review Vocab. Diploid – full set of chromosomes

Meiosis

Sexual 2 cell Divisions Result: 4 cells Chromosomes are

randomly distributed. Cells are Haploid

Haploid – half set of chromosomes

GeneticsII. Main Concepts…

a. Sexual reproduction involves the random distribution of genes.b. We have thousands of genes.c. Genes determine your traits.d. Genes line up on your chromosomes.e. Chromosomes are in the nucleus of the cell.f. Chromosomes duplicate and divide in cell division.g. Chromosomes are typically in pairs.h. A diploid cell has a complete set of chromosomes.

GeneticsFrog: 13

Pea: 7

Apple: 17Chimpanzee: 24

Dog: 39

How do we know traits are inherited from our parents?

A: Gregor Mendel

III. Gregor MendelWho was he? An Austrian Monk.What did he do? Experiments with pea plants.

Mendel’s Experiments

Short pea plants X Tall pea plantsQ: What did he get?A: All Tall pea plants!!!!

Then, Tall X Tall pea plantsQ: What did he get?A: 787 Tall pea plants& 277 short pea plants

The results as a ratio:

787/277= 2.8/1 =

3:1 ratio of tall to short pea plants

Conclusions from Mendel’s Experiments

1. Factors = Genes2. Law of Dominance: in any pair of genes, one may

hide the appearance of the other.Green pea pods X yellow pea pods

Outcome: F1 Yellow

Dominant: expressedRecessive: masked, hidden, not expressed3. Law of Segregation: During Meiosis chromosomes

separate, and genes separate also.4. Law of Independent Assortment: the pairs of genes

(and chromosomes) separate randomly!

Genetics Vocabulary• PHENOTYPE: physical

appearance; what it looks like.

• GENOTYPE: genetic make-up; combination of genes.

• Represented by 2 letters.• 3 possible genotypes.

• EX. Green pea pod, pink flower, tall stems

EX. GG, Gg, gg

Genetics Vocabulary• DOMINANT: allele that

hides(masks) the other.

• RECESSIVE: allele that is hidden (masked) by the dominant allele.

• EX. • T = dominant allele for tall

pea plants.

• EX. • t = recessive allele for short

pea plants.

Genetics Vocabulary• ALLELE: one half of a gene.• **2 alleles make up a

gene!!

• You get one allele from one parent and the other allele from the other parent.

• Alleles can have different forms (dominant or recessive)

EX. T = dominant allele t = recessive allele

Gene = TT, Tt, or tt

Genetics Vocabulary

• Homozygous: gene with the same alleles.

• Heterozygous: gene with different alleles.

• Ex. TT or tt

• TT = homozygous dominant

• tt = homozygous recessive

• Ex. Tt = heterozygous

Human Genetics

Dimples

Cleft Chin

Widow’s Peak

Free and Attached Ear lobes

Second toe is longer than big toe

Tongue rolling

Traits due to 1 gene

• Dominant

• Free earlobe• Left handedness• Tongue rolling• Left arm on top• Left thumb on top

• Recessive

• Cleft chin• Dimples• Attached earlobe• Second toe longer• Widow’s peak• Double jointedness

Complex Genetics

• Incomplete Dominance

• The dominant allele is not completely dominant over the recessive allele.

• Result: a blend of the 2 forms of the trait.

• R – red flower• r – white flower

• RR – red• rr – white• Rr - pink!

Complex Genetics• Co-Dominance

• There are 2 dominant alleles for the trait.

• Result: Both show up equally.

• Ex. B – black feathers• W – white feathers

• BB – black feathered chicken

• WW – white feathered chicken

• BW – black & white checkered feathered chicken!

Both are dominant allels and will display in the offspringWWXBB=BW

Blood Types

Blood Type Alleles

• IA – A blood• IB – B blood• i – O blood

Blood Type Genotypes

• IA IA = A blood• IA i = A blood• IBIB = B blood• IBi = B blood• ii = O blood• IAIB = AB blood

or Blood type and Wha

If Beyonce is Heterozygous A and Jayz has codominant AB..What would be the outcome of their babies…

A O

A AA

B

If Beyonce has is Heterozygous a and Jayz has codominant AB..What would be the outcome of their babies…

If Beyonce is Heterozygous A and Jayz has codominant AB..What would be the outcome of their babies…

A O

A AA

B

If Beyonce has is Heterozygous a and Jayz has codominant AB..What would be the outcome of their babies…

Shakira has a homozygous O blood and her child has heterozygous AB. Can the husband be homozygous A?

O O

A

B

X-Linked Traits

• The allele is attached to the X chromosome.

• Can only be passed from Mother to son, Mother to daughter, or father to daughter.

X-linked genes means…

• Girls can be normal or Carries but Boys will be AFFECTED the most.

X Y

X XX XY

X XX XY

Are you Colorblind?

Hemophilia X-Linked

Lacks clotting in the blood

Menkes DiseaseX-linked gene causes kinky hair and mental disorders

Pedigree

• How many generations?

• How many females?

• How many males?

• How many great grandchildren?

• Who has the disease?

Karyotypes

• Def: picture of chromosomes

• Chromosomal Genetic Disorders:

• Too many or too few chromosomes.

• Usually results in death or sterility.

• Ex. Down’s syndrome

Karyotypes

• Def: picture of chromosomes

• Chromosomal Genetic Disorders:

• Too many or too few chromosomes.

• Usually results in death or sterility.

• Ex. Down’s syndrome

Down Syndrome

O

• Ex. Turner Syndrome

• 1 in 5000

• Usually sterile

Turner Syndrome

Ex. Edwards Syndrome (Trisomy 18)• Most

fetuses abort.

• If survives, • 50% do not

survive past 1 week.

• 90% do not survive past 1 yr.

Sickle Cell Anemia: genetic disorder where blood cells are oval shaped causing pain

Tri-18

Huntington’s neurodegenerative genetic disorder that affects muscle coordination and leads to cognitive decline and psychiatric problems

PKU and Fragile XPKU-unable to break down proteins

Fragile X- mutation in the X chromosome causing mild retardation and autism

TaySach –destroys the nervous system neurons/brain and is life threatening

Destroys brain function

Gel Electrophoresis