Presentation on theme: "Danny Gardner and Merline Maxi 2/1/10 Period 9/10."— Presentation transcript:
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?