1. Il “Dogma Centrale” della Biologia

9. Cromosomi umani condensati

11. Bandeggio cromosomico

13. Genes and Diseases
1902, A. Garrod proposes the “one gene one enzyme ” hypothesis (upon Bateson’s suggestion)
Garrod, A. E. The incidence of alkaptonuria: a study in chemical individuality. Lancet II: , 1902.

14. The Genetic Basis of Diseases: Chromosomal Aberrations
1956 Human karyotype is defined (Tjio J.H & Levan A The chromosome number of man. Hereditas 42, 1-6)
1970s chromosome banding techniques
Many known pathological aberrations
aneuploidies (e.g., Down syndrome)
Translocations (e.g., leukemias)
Deletions (e.g., Prader-Willis syndrome, del 15q11-13)

15. The Genetic Basis of Diseases: Single Gene Mutations
Pathogenic Mutation: any change in the DNA sequence leading to a disease
Aa changes (e.g., cystic fibrosis)
Non-sense changes
Splicing mutations
Deletions/insertions (affecting or not the ORF): e.g., DMD

16. The Genetic Basis of Diseases: Somatic Mutations and Cancer
Mutations in ‘tumour suppressor genes’ (Rb, BRCA1 e 2 etc.)
Mutations in oncogenes (Myc, Src)
Activating mutations
Chromosomal aberrations (e.g., CML).
Mutations in genes involved in DNA repair mechanisms (e.g., colon cancer).

17. The Genetic Basis of Infectious Diseases
Genetic material introduced into the host (DNA or RNA)
Expression of exogenous genes (including oncogenes, e.g., HPV16-E6)
Can integrate in the host genome (e.g., HIV)
Many polymorphisms are known to either increas or decrease susceptibility to infectious disease (e.g., HIV-protective CC chemokine receptor 5-Δ32/Δ32)