Danny Gardner and Merline Maxi 2/1/10 Period 9/10.

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Danny Gardner and Merline Maxi 2/1/10 Period 9/10

Summary of Sickle Cell Anemia  a disorder in the red blood cells causing them to be “sickle” shaped  Prevents oxygen from reaching certain organs and blood cells going through blood vessels.  Symptoms include: frequent infections, anemia, crises, delayed growth, strokes, and jaundice. Interesting Fact:  People who have sickle cell have an average life span of 30 years  Unlike normal red blood cells, which can live for 120 days, sickle- shaped cells live only 10 to 20 days.

What Chromosome is Sickle Cell located On?  Located on chromosome eleven  causes the hemoglobin molecules to form incorrectly giving blood cells its a crescent shape.

Mode of Inheritance  Autosomal recessive pattern  Both of the recessive genes must be present in order for the organism to be diagnosed with the disease.

What Are Alleles?  Genes in a chromosome for a specific feature.  Each given by a parent (2)  How are alleles represented?  Capitals equal dominate  Ex. T  Lower Case equals recessive  Ex. t.

Punnett Square Examples SSSsSs SsSs ss SS ss Ss S s S S S S ss s s Heterozygous dominate Homozygous recessive Homozygous dominate

Explaining Probability S s S s  Ratios  Must equal up to total amount of possibilities Homozygous dominant : heterozygous dominant : homozygous recessive 12 1 : : 1 SS : 2 Ss : 1 ss  Percentages  Must equal up to 100 _p_ 100 Homozygous dominant: heterozygous dominant : homozygous recessive 25% : 50% : 25% 25% SS : 50% Ss : 25% ss

SS? Ss? ss? What these letters mean! If S is the dominant allele for Sickle cell and s in the recessive, we can infer that: Phenotype (what you SEE) SS- normal Ss-normal (Sickle cell trait) carrier ss- SICKLE CELL Genotype (what is in the GENES) SS-homozygous dominant Ss-heterozygous dominant ss- homozygous recessive SSSsSs SsSs ss S s S s

Genotype and Phenotype Probability SSSs ss S s S s Phenotype  Ratios- 1 SICKLE CELL: 3 normal  Percentages- 25% SICKLE CELL: % normal Genotype  Ratios- 1 SS: 2 Ss: 1 ss  Percentages- 25 % SS: 50% Ss: 25% ss

Student Practice Phenotype: S s S s Ss SS Ss ss 25% Sickle Cell: 75% normal Genotype: Percentage= Ratio=1 Sickle Cell: 3 normal Ratio= Percentage= 1SS: 2 Ss: 1ss 25% SS: 50% Ss: 25% ss

3 Generation Hypothetical Pedigree Ben Julie Damon Jane AlexChris Sarah Clark Loui s Carolin e Mary Key: Circle- Male Square Feminine Light blue- Person is healthy but may carry recessive “bad” gene. Can be heterozygous dominate or homozygous dominate. Dark Blue- Person is affected carries homozygous recessive.

Student Practice Craig Lisa Sean Lora John Tom SamKateErica Bill Nina Key: Circle- Male Square Feminine Light Purple- Person is healthy but may carry recessive “bad” gene. Can be heterozygous dominate or homozygous dominate. Dark Purple- Person is affected carries homozygous recessive. 1.Why do you think Craig and Lisa had a sickle cell child? 2.How is it possible that Sean and Sam had a healthy child? 3. What alleles do Craig and Lisa both carry?