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Sickle Cell Anemia. By: Dasia Davis Gabriella Mirenda Lorena Sposato. What is Sickle Cell?. Inherited blood disorder that affects red blood cells Red blood cells contain Hemoglobin S which is abnormal
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Sickle Cell Anemia By: Dasia Davis Gabriella Mirenda Lorena Sposato
What is Sickle Cell? • Inherited blood disorder that affects red blood cells • Red blood cells contain Hemoglobin S which is abnormal - Become sickle shape and makes it difficult fitting through small blood vessels and less blood reaches body. • Symptoms of sickle cell include 1. Abdominal Pain 2. Delayed growth and puberty 3. Bone Pain 4. Breathlessness 5. Fever 6. Jaundice 7. Paleness 8. Ulcer in the lower legs Interesting facts: with each pregnancy, 2 people have sickle cell traits have: • A 25% chance of having an unaffected child with normal hemoglobin • A 50% chance of having a child who also is a carrier. • A 25% chance of having a child with sickle cell anemia
What Chromosome is your disorder located on? • The HBB gene is found in the region 15.5 on the short (p) arm of human Chromosome 11.
Mode of Inheritance • Autosomal Recessive genetic disorder • Two copies of the altered gene must be present on the autosomes in order for the person to be affected by the trait.
Alleles • 2 alleles, one from each parent • Alleles are represented by: -RR Rr rr • Dominant- expressed in a person with only one copy of that gene present. • Recessive- expressed in a person with two copies of the gene is present.
Punnett Squares s s S d d s d d
Ratios and Percentages S Ratios: s • Homozygous dominant: Heterozygous dominant: Homozygous recessive • : 2 : 1 • 1SS : 2Ss : 1ss S s Percentages: Homozygous dominant: Heterozygous dominant: Homozygous recessive 25% : 50% : 25% 25% SS : 50%Ss : 25% ss
Model Explanation • SS represents the dominant allele SICKLE and s represents the recessive allele • Phenotype: • SS= No disease • Ss= Sickle cell anemia • ss= Sickle cell anemia • Genotype: • SS=Homozygous dominant • Ss=Heterozygous dominant • Ss=Homozygous recessive S s S s
Phenotype and Genotype • Phenotype -Ratios- 3SS: 1ss -Percentages: 75% SS: 25% ss • Genotype -Ratio- 1SS: 2Ss: 1ss -Percentages- 25% SS: 50%Ss: 25%ss S s S s
Student Practice Father’s Genes M O T H E R’ S G E N E S S s Genotype: Ratio: Percentage: Phenotype: Ratio: Percentage: S 3SS: 1ss 75%SS: 25% ss 1SS: 2Ss: 1ss s 25%SS: 50%Ss: 25%ss
3 Generation Pedigree Ricky Martin Sarah Lizzie Zac Alex Miranda Carl Fergie Cashmere Bob Marley Vanessa Red= Person is Healthy, with a possible chance of carrying a “bad” gene. Yellow= Person is affected
Student Practice Bob KEY • Circle: Female • Square: Male • All Red: Person is healthy. • All Yellow: Person is affected. • Red/Yellow: Carrier. Kim Charlie Brian Lily Jen Ben Gaby Kait Ana Susan Questions: Answers: 1.) How many sickle cell genes are need to inherit the disease? • It occurs when a person inherits two sickle cell genes. • It means the person carries one “bad” gene and one “healthy” gene, but is essentially healthy and has no symptoms of the disease. 2.) What does it mean, when a person is a “carrier” of the gene?