1. Sickle Cell Anemia 1) Single nucleotide substitution (“point mutation”) in the gene for the beta chain of hemoglobin. 3) Beta chain synthesized from the sickle-cell allele does not “fold” correctly and hempglobin molecules “clump” together forming a red blood cell that resembles a sickle. 2) Different amino acid gets placed in the peptide chain.. 4) Sickled cells die early (10-20 days vs. 120 days) producing anemia. 5) Sickled cells clog the fine capillaries, leading to lack of oxygen in target organs.

2. http://bio.winona.msus.edu/berg/308s04/Lec-note/19-new.htm

3. Rapid breakdown of sickled cells Hemoglobin molecules “clump” Sickle-shape red blood cells Skeletal problems Impeded circulation Organ damage Pain Infection risk Overactive bone marrow Fatigue Impaired development Anemia

4. http://www.ncbi.nlm.nih.gov/books/bv.fcgi?call= bv.View..ShowSection&rid=gnd.section.98

5. http://peptide.ncsa.uiuc.edu/tutorials_current/Sickle_Cell_Anemia/SC2001/intro.html

6. http://www.blackwellpublishing.com/ridley/images/sickle_cell_anaemia.jpg

7. http://anthro.palomar.edu/synthetic/synth_7.htm Why is SCA so common in some areas?

8. http://anthro.palomar.edu/synthetic/synth_7.htm

9. Different origins (independent mutations) of the SCD allele