Please be kind. A harsh genetic disorder is no one’s choice. Keep all comments about any pictures to yourself.

Thank you.

Raashmi Patalapati, Rizzlyn Melo, Erica Price

February 1, 2010Period 3

• Three different types of albinism: OCA-1, OCA-2, and OCA-3

• OCA-1: occurs on chromosome 11•OCA-2: occurs on chromosome 15•OCA-3: occurs on chromosome 9

Summary of Albinism Inherited disorderToo little, or complete lack of, melanin Shows very pale, white skin and hair. Causes eyes to appear pink as well as creates eye problems.

Can occur in humans, animals, or plants.

Mode of InheritanceThe three types of albinism are acquired

through the chromosomes.It is an autosomal recessive disorder. Autosomal recessive means that in order to

show the disease you must have two of the recessive alleles. Two copies of the gene must be mutated.

There is a equal chance of males and females showing and carrying albinism

•Each person has two alleles per gene•One comes from the mother, the other from the father•Dominant and recessive alleles are represented by letters.

• Dominant- capital letter•Recessive- lowercase letter

•Dominance is when the allele is able to take over recessive alleles. •Recessiveness is when the allele can be taken over by a dominant allele.

•Punnett squares represent a particular cross of the parent’s genes to predict the reproduced outcome.

•Mother is on the left and father is represented on the top.

a aa

A Aa Aa

a aa aa

A aa

A AA Aa

a Aa aa

a aa

a aa aa

a aa aa

A aa

a Aa aa

a Aa aa

•Ratios-2 Aa: 2 aa

•Percentages - 50% Aa: 50% aa

a aa

A Aa Aa

a aa aa

Letters in Punnett Squares

•What these letter mean! AA? Aa? aa?

•PhenotypeAA= doesn’t show

Aa= doesn’t show

aa= shows

•GenotypeAA= not a carrier

Aa= carrier

aa= carrier

If A represents the normal healthy allele and a represents the recessive albino allele, then we can assume that:

a aa

A Aa Aa

a aa aa

Punnett Squares(cont.)

•Phenotype

-Ratios- 2 shows: 2 doesn’t show

- Percentages- 50% shows : 50% doesn’t show

•Genotype

- Ratios- 2 Aa: 2 aa

- Percentages- 50% carries, but doesn’t show:

50% carries and shows

100% carries

Genotype:Ratio: 4:4 carriers

Percentage: 100% carriers

Phenotype:Ratio: 4:4 doesn’t show

Percentage: 100% doesn’t show

A A

a Aa Aa

a Aa Aa

Mother’s genes

Father’s genes

*Autosomal Recessive

White= Person is fine. May possibly carry the recessive “bad gene.” Can have one “health” and one “bad” gene of two “healthy genes.”Black= Person is affected. Has 2 “bad” genes.

I

II

III

KeySquare: maleCircle: female

I

II

III

1. What are the chances of two carriers of albinism passing it on to their children? (Not necessarily showing? 2. Why is it not possible that another child of the couple in generation I, could not show OR be a carrier of albinism? 3. If the unmarried male in generation II, were to reproduce, what are the possible outcomes of his children?

Key: circle=female square=male shaded in=infected not shaded in=carrier dot= healthy