Warm Up 2/11

• Sit with your baby partner.• What is an example of a chromosomal

disorder?• What is an example of a gene disorder?

Important Dates

• Genetic Quiz!• Baby Project DUE Next time!• You picked up a review at the door!• Six Weeks Test on 2/20!

Genetics Quiz

Types of Inheritance

Simple, Co-dominance, Incomplete Dominance, Multiple Alleles, Sex-

Linked

Simple Dominance

• 1. Simple Dominance:– One Trait is expressed over another in the

heterozygous condition.– Mendelian Genetics

– Ex. Pure Tall X pure Short = Hybrid Talls

T Tt

t

Incomplete Dominance

• The heterozygous condition has a new phenotype – it is blended

• Ex. Pure Red (RR) X Pure White(WW) = Hybrid Pink (RW)

Notice that they are both dominant traitsR R

W

W

Snap Dragons

Notice that the offspring are all pink.

What would happen if two PinkSnapdragons mated? (RW X RW)

What would be the Phenotypic Ratio?

Genotypic Ratio?

Co- Dominance

• Both traits are equally expressed in the heterozygous condition.

• Ex Pure Black X Pure White = Hybrid Checkered

B BWW

Chickens

COWS

Sickle Cell Anemia

• Codominance between normal and sickle gene (S) and (N)

• NN: Normal Hemoglobin• NS: Carrier (1/2 normal : ½ Sickled )• SS: has sickle cell anemia

Practice

• A male who is a carrier for sickle cell anemia, is married to a female who is also a carrier. What is the chance that a child may have normal hemoglobin? Sickle Cell?

Polygenetic Inheritance

• A non-Mendelian form of inheritance in which a particular trait is produced by the interaction of many genes

• Ex. Height, Skin Color, Eye color, Hair color

Multiple Alleles

• Some traits have more than 2 possible alleles.

• Ex. Human Blood type 3 alleles: IA, IB, i

• The allele indicates the type of markers found on the blood cells.

Genotype(s) Phenotype

IAIA, IAi, A Type Blood

IBIB, IBi B Type Blood

IAIB AB Type Blood

ii O Type Blood

Why is type O the Universal Doner?

• http://www.nobelprize.org/educational/medicine/bloodtypinggame/

Lets practice

• A female who is Heterozygous for type A blood, has children with a male who is type O blood.

What is the chance of their children having 0 type blood?

Blood Typing Practice

• If a child has TYPE O Blood. What genotypes could the parents have?

• List all possible crosses.

Sex-Linked Inheritance

• Traits controlled by genes located on sex chromosomes. – The 23rd pair of human chromosomes determine the

sex of an individual. ( can be identified on a karyotype)

• T. H Morgan accidentally discovered while studying fruit flies.

• Review: Males (XY) Females (XX)

Human Sex-Linked Disorders

• 1. Red-Green Colorblindness

• 2. Hemophilia A

• 3. Duchenne’s muscular Dystrophy

Colorblindness

• For sex-linked traits, you must write genotypes like:

• XCXC: Normal color vision female• XCXc: Normal color vision female (carrier)• XcXc: Color-blind female• XCY: Normal Color Vision Male• XcY: Color-Blind Male

Example

• Female with colorblindness has children with a normal vision male.

• What are the genotypes and phenotypes of offspring?

What do you need to remember?

• 1. Males pass their X-linked allele to all their daughters. (never to sons)

• 2. Heterozygous females have a 50% chance of passing a recessive allele to all her children.

• 3. Males receiving the recessive X from mom will ALWAYS express the trait.

Why are males more likely to get a sex-linked disorder?

Sex-Linked Examples

• Hemophilia is a disorder dependent on a sex-linked recessive gene (Xh ). Normal Blood is dominant (XH)

• A. Find the genotype and phenotype ratios of a cross between a hemophiliac man and a homozygous normal woman.

Practice

• Find a genotype and phenotype ratios of a cross between a normal woman, whose father was a hemophiliac, and a normal man.

Work on Baby Project!!

• It’s due next time!!!