ALBINISM Greer Manton, Sydney Gilbert & Monica Starbinski 2/1/10 – Period 2

Please be respectful during this PowerPoint. The photos you may see today are unlike many others. Keep in mind that they are of real people, and you never know if someone has a person close them that has this. Thank You, Sydney, Monica and Greer

What Chromosome? Albinism is a genetic order, which is caused by a gene on the ninth X (female) chromosome.

Alleles Alleles – an alternative form of a gene, which is located on a specific part of a certain chromosome. 2 alleles per human gene. Recessive (aa): -trait will only appear if a dominant allele is not present. -homozygous Dominant (AA, Aa): -overpowers the recessive allele. -heterozygous

Summary Of Albinism Albinism – a rare, inherited, disease that you are born with, causing a lack in pigment or melanin. Usually, the person’s hair, eyes, and skin are affected. Symptoms – Extremely light colored skin light/white colored hair pale blue/grey eye color, sometimes even pink very high risk of sunburn and skin cancer vision problems *Interesting Facts* There is no cure for Albinism, but precautions can be taken to alleviate the symptoms. - Staying out of the sun - contacts or seeing an optician

Mode Of Inheritance Albinism is recessive. A male would have to inherit one affected X chromosome and females would have to inherit two affected X chromosomes to have the disorder. It is not dominant because you do not get it every time, if one parent is a carrier. Both parents must contain the gene, whether they have the disease or not. It is autosomal because you need two copies of the affected gene must be present in order for albinism to occur.

Punnett Squares A – dominant (normal gene) a – recessive (affected albinism gene) AA aa Aa A a aa a A a A aa A A

Probabilty Ratios 1 : 3 1aa : 3Aa aaAa A A a a Percentages 25% : 75% 25% aa : 75% Aa

Hypothetical Pedigree Key White – Healthy unaffected person. May carry one albinism gene. Orange – Affected with albinism, has two of the damaged genes LauraJonathon Andrew LeahNickClaire George MaryMax Kim Ashley

Hypothetical Pedigree (Student Practice) Choose a Female and a Male Who is married to who The children they have And probability of them being affected. The Rest is up to you! Key: Pick 2 colors. One for non effected One for affected

Pedigree Question and Answer: 1.How many affected parents are needed to produce a child with albinism? 2.What are the chances that the third generation of children will get albinism if only one child in the second generation was affected? 3.If both parents carry the gene what’s the chance that the child will not get albinism?