Human Genome Project

 Human Genome Project

Human Genome Project Introduction

• Genome: A genome is the entire DNA in an organism, including its genes. The human genome is estimated to contain 30,000–40,000 genes that are divided among the 23 chromosomes. The 23 different chromosomes, 22 are autosomes (numbered 1–22) and 1 pair of sex chromosomes (X and Y). The functions of over 50% of discovered genes are not known.
• Gene mapping: It is the process of identifying and sequencing each and every human gene of the human genome. The map of the human genome provides a picture of locations, and structures of genes. Genetic mapping (linkage analysis): A genetic map describes the order of genes and defines the position of a gene relative to other loci on the same chromosome.
• Physical mapping: Physical mapping indicates the position of genes in a chromosome, which is determined by physical distances (measured in base pairs) between genes.

Organisms and their genomic size are presented in

The human genome project (HGP) is an international scientific research project to understand the genomes of humans and other organisms.

It was started in 1990 under Dr James D Watson at the United States National Institute of Health.

In addition to the United States, the international consortium comprised geneticists in the United Kingdom, France, Germany, Japan, China, and India.

Goals of Human Genome Project

Understand and identify all genes of the human genome.

Determine the human DNA sequence: The primary focus of the HGP was to obtain DNA sequence for the entire human genome.

The goal was to map all genes of the human genome and also to map human inherited diseases. Thus included creation of genetic maps, development of physical maps, and determination of the complete human DNA sequence.

Develop software for large-scale DNA analysis, store all found information in databases and improve tools for data analysis.

Transfer-related technologies to the private sector

Collect and distribute data

Study the ethical, legal, and social issues (ELSI) of genetic research that may arise from the project.

Components involved in human genome are diagrammatically shown in

All humans have unique gene sequences. Therefore, the data published by the HGP does not represent the exact sequence of each and every individual’s genome.

It is the combined genome of a small number of anonymous donors.

The HGP genome is a scaffold for future work in identifying differences among individuals.

Uses of Human Genome Project

Human genome project will shed light on a wide range of basic questions, to identify the number of genes in humans, how cells work, how living things evolved, how single cells develop into complex creatures, and what exactly happens when we become ill.

The understanding of the genome provides clues for:

• Etiology of cancers, Alzheimer’s disease, etc.
• Defining the pathogenesis of a disease and to study the disease processes at molecular level.
• Susceptibility of an individual to a variety of illnesses, e.g., carcinoma breast, disorders of hemostasis, liver diseases, cystic fibrosis, etc.
• Predict new ways to prevent a number of diseases that affect the human beings.
• To diagnose and treat disease. Target genes for treatment and management of diseases.
• Human development and anthropology: Analysis of similarities between DNA sequences from different organisms helps to study evolution.
• Researcher: By visiting the human genome database on the Worldwide Web, researcher can examine what other scientists have written about the gene.

Human Genome Project Ethical Issues

Human genome project helps to identify disease-causing genes, thereby can lead to improvements in diagnosis, treatment, and prevention.

It is estimated that most individuals harbor several serious recessive genes.

However, completion of the human genome sequence and determination of the association of genetic defects with disease has raised many new issues with implications for the individual and mankind.

Genetic Mutations

Mutations are alterations in the genome of a cell.

Genome Of A Cell Mechanism

• As a result of errors during DNA replication or cell division
• Ineffective DNA repair mechanisms
• Damage to DNA caused by endogenous and exogenous toxins

Genome Of A Cell Types of mutations

• Mutations according to affected cell population

Ethical issues in human genome project (HGP).

• Fairness in the use of genetic information
• Privacy and confidentiality
• Psychological impact and stigmatization
• Genetic testing
• Reproductive issues
• Education, standards, and quality control
• Commercialization
• Conceptual and philosophical implications.
• Chromosomal aberrations
• Gene mutations

Human Genome Project Based on the affected cells

• Germline mutation (gametic mutation):
  • Mutations in the cells from which egg or sperm cells develop
  • These mutations can, therefore, be passed on to offspring.

Human Genome Project Somatic mutation

Acquired mutations that are present only in certain somatic cells

• Primarily affect only one allele of a gene.
• Do not occur in the germline and therefore cannot be passed on to offspring via the ovum or sperm
• Almost all malignancies are preceded by a somatic mutation.

Human Genome Project Chromosomal aberrations

• Chromosomal aberrations are mutations affecting large segments of DNA
• They may be visible on karyogram
• Numerical chromosomal aberrations or structural chromosomal aberrations (discussed earlier)