Trisomy | Down's vs Edward's vs Patau's Syndrome

Introduction to Trisomy Syndromes00:00:00

Overview of Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Patau syndrome (trisomy 13), highlighting their respective frequencies in the population.

Dosage Compensation and Lethality00:01:25

Explanation of how extra chromosomes disrupt dosage compensation, leading to gene overexpression, which correlates with the varying lethality rates of each syndrome.

Chromosome Size and Gene Count00:02:12

Comparison of chromosome sizes and the number of protein-coding genes. The 21st chromosome is the smallest, which explains why Down syndrome is less lethal and more common than Edwards and Patau syndromes.

Conclusion and Summary00:04:43

Final analysis confirming that larger chromosomes result in more disrupted genes during dosage compensation, explaining why Patau syndrome is significantly rarer than others.