Sickle Cell Genetics Webinar

Introduction

• Presenter: Bruce from MiniPCRBio
• Purpose: Demo of a sickle cell genetics lab using gel electrophoresis
• Target Audience: Students and teachers
• Tools: Worksheets available via link

Lab Overview

Goals

• Understand sickle cell disease
  • Physiology and genetics
• Analyze DNA sequences of a fictional family
• Use biotechnology tools

Techniques

• Gel electrophoresis
• Based on prior PCR and restriction digest

Educational Value

• Teaches multiple topics (disease genetics, protein structure, biotechnology)
• Adaptable from introductory to college level

Sickle Cell Disease

Background

• Hemoglobin: Protein in red blood cells carrying oxygen
• Structure: Tetramer (2 alpha, 2 beta globins)
• Mutation: In beta-globin gene (HBB)

Mutation Impact

• Normal vs. Sickle Cell Version
  • Normal: Glutamic acid (hydrophilic)
  • Sickle Cell: Valine (hydrophobic)
• Effect: Causes red blood cells to sickle, leading to crises

Genetics

Alleles

• HBA: Normal
• HBS: Sickle cell
• Located on chromosome 11
• Inheritance: Recessive disease

Genotypes

• AA: Normal
• AS: Sickle cell trait (heterozygote)
• SS: Sickle cell disease

Natural Selection

• Prevalence: Common in areas with malaria

Gel Electrophoresis Process

Concept

• Separates DNA by size
• DNA moves through a gel matrix towards a positive charge

Practical Steps

• Pouring a gel using agarose
• Loading DNA samples
  • Use of DNA ladder to determine fragment sizes

Experiment

• DNA Fragments: 400 base pairs, can be cut to 250 and 150 base pairs
• Restriction Enzyme: DDE1
• Outcome: Determines genotype based on DNA fragment sizes

Family Case Study

Robinson Family

• Jacqueline: Heterozygote
• Corey: Normal
• Samuel: Normal
• Marie: Sickle cell disease

Additional Insights

Sickle Cell Trait

• Offers some protection against malaria

SNP (Single Nucleotide Polymorphism)

• Different nucleotide changes amino acid

Modern Techniques

• CRISPR: Potential for gene editing to treat sickle cell
• Bone Marrow Transplant: Replaces diseased cells

Conclusion

• Relevance: Real-world application
• Adaptability: Suitable for various educational levels
• Future Webinars: Upcoming session on enzyme activity and DNA structure

FAQs

• Crisis Frequency: Related to oxygen binding
• Other Hemoglobinopathies: Include thalassemias, HbC allele
• Testing Methodology: Lab demo, not a real diagnostic test

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This webinar provides a comprehensive look at sickle cell genetics through a practical lab approach using gel electrophoresis, suitable for educational purposes across different levels.