Human Genome Project and Genomic Concepts

Introduction to the Human Genome Project (HGP)

• Presentation Title: The Human Genome Project and Cool Stuff That Came From It.

• Presenter: Dr. Lori Banks, Prairie View A&M University (PVAMU).

• Key Themes: Understanding genomic history, the reality of protein-coding DNA, and the broader implications for medicine, ethics, and our understanding of race.

Evolutionary and Functional Realities of the Human Genome

• Protein-Coding Constraints:     * Only approximately $2\%$ of the human genome is used to make RNA and proteins as traditionally taught in molecular biology.     * Research is ongoing to determine the specific functions of the remaining $98\%$ of the DNA sequence.

• Complexity vs. Gene Count:     * Biological complexity is not directly proportional to the total number of genes an organism possesses.     * Humans are not the most complex organisms when measured by the size of the genome or the total count of genes.

• Scientific Outcomes of the HGP:     * The project produced essential tools for auxiliary research across various fields.     * It challenged pre-existing scientific biases and raised new questions rather than providing a final, definitive answer to all genomic inquiries.

Comparative Genomics: Size, Gene Count, and Density

• General Concept 21.3: Genomes vary significantly in overall size, number of genes, and gene density (number of genes per million base pairs).

• Measurement Units:     * $Mb$ = Million base pairs.     * Statistics are based on the haploid genome size, representing a complete set of genetic information.

• Bacteria:     * Haemophilus influenzae: Haploid Size: $1.8\,Mb$; Genes: $1,700$; Density: $940\, ext{genes/Mb}$.     * Escherichia coli: Haploid Size: $4.6\,Mb$; Genes: $4,400$; Density: $950\, ext{genes/Mb}$.

• Archaea:     * Archaeoglobus fulgiclus: Haploid Size: $2.2\,Mb$; Genes: $2,500$; Density: $1,130\, ext{genes/Mb}$.     * Methanosarcina barkeri: Haploid Size: $4.8\,Mb$; Genes: $3,600$; Density: $750\, ext{genes/Mb}$.

• Eukaryotes:     * Saccharomyces cerevisiae (yeast/fungus): Haploid Size: $12\,Mb$; Genes: $6,300$; Density: $525\, ext{genes/Mb}$.     * Utricularia gibba (floating bladderwort): Haploid Size: $82\,Mb$; Genes: $28,500$; Density: $348\, ext{genes/Mb}$.     * Caenorhabditis elegans (nematode): Haploid Size: $100\,Mb$; Genes: $20,100$; Density: $200\, ext{genes/Mb}$.     * Arabidopsis thaliana (mustard family plant): Haploid Size: $120\,Mb$; Genes: $27,000$; Density: $225\, ext{genes/Mb}$.     * Drosophila melanogaster (fruit fly): Haploid Size: $165\,Mb$; Genes: $14,000$; Density: $85\, ext{genes/Mb}$.     * Daphnia pulex (water flea): Haploid Size: $200\,Mb$; Genes: $31,000$; Density: $155\, ext{genes/Mb}$.     * Zea mays (corn): Haploid Size: $2,300\,Mb$; Genes: $32,000$; Density: $14\, ext{genes/Mb}$.     * Ailuropoda melanoleuca (giant panda): Haploid Size: $2,400\,Mb$; Genes: $21,000$; Density: $9\, ext{genes/Mb}$.     * Homo sapiens (Human): Haploid Size: $3,000\,Mb$; Genes: $21,300$; Density: $7\, ext{genes/Mb}$.     * Paris japonica (Japanese canopy plant): Haploid Size: $149,000\,Mb$; Genes and density not determined (ND).

Modern Genetic Insights and Ethical Considerations

• Genetic Randomness: Humans exhibit high levels of genetic variation; there is no biological "normal" human genome.

• Inter-species Similarity: Organisms across different taxa are more genetically similar than previously assumed.

• Technological Advancement: DNA sequencing transition from high-cost endeavors to very cheap, accessible technology.

• Medical Applications:     * Personalized Medicine: Tailoring treatments based on an individual's unique genetic profile.     * Vaccine Development: Using genomic data to accelerate the creation of immunizations.

• Gene Patenting Ethics:     * Early 2000s: Several genes linked to diseases were patented, including $BRCA1$ and $BRCA2$ (breast and ovarian cancers), $HNPCC$ and $FAP$ (colon cancers), $CFTR$ (cystic fibrosis), and $HFE$ (hemochromatosis).     * Supreme Court Ruling (2013): The US Supreme Court ruled that naturally occurring gene sequences cannot be patented; they do not belong to any individual or corporation.

• Race vs. Genetic Heritage:     * Genetic heritage and the social construct of race are distinct concepts.     * Race has no scientific basis in terms of discrete genetic categories.

Recessive Genetic Disorders: Cystic Fibrosis (CF)

• Genetic Basis: Caused by mutations in the $CFTR$ gene.

• Inheritance Pattern: CF mutations segregate as a recessive trait.

• Clinical Presentation: Patients produce abnormally thick mucus in the lungs, which obstructs airways.

• Impact on Life Expectancy:     * Historically: Fatal during childhood.     * Modern Medicine: Current life expectancy is approximately $35$ years.

• Prevalence Statistics:     * $1$ in $2,500$ Caucasian newborns.     * $1$ in $17,000$ African American newborns.     * $1$ in $32,000$ Asian newborns.

Case Study: Personal Genomics (23andMe Example)

• Individual Profile: Dr. Lori Banks (LB).

• Ancestry Composition Results:     * $100\%$ Sub-Saharan African.     * $51.2\%$ West African.     * $41.5\%$ Ghanaian, Liberian, and Sierra Leonean.     * $15.5\%$ Nigerian.

• Scientific Conclusion: Race is not the same as genetic inheritance; genetic data provides specific geographic and ancestral lineage information rather than confirming social race categories.

Questions & Discussion

• Question: What do you know/remember about the Human Genome Project?     * Context: This open question serves to gauge prior knowledge of the landmark international research project.

• Question: How much of our DNA is being used to make proteins?     * Response: Approximately $2\%$.

• Question: How many genes are in the human genome?     * Response: Approximately $21,300$ (as listed in Table 21.1).

• Question: What are some questions that can be explored by sequencing and comparing genomes?     * Context: This encourages inquiry into evolutionary relationships, the basis of disease, and functional genomics.

• Question: If you determine the sequence of a naturally occurring gene, should you be able to patent it?     * Historical Context/Response: While many were patented in the early 2000s, the 2013 Supreme Court ruling established that naturally occurring sequences cannot be patented.