Anti-Aging Research

Human Genetics

The science of genetics deals with genes and biological inheritance, by which a predisposition to parental traits is passed to offspring at conception. Humans began applying knowledge of genetics in prehistory with the domestication and breeding of plants and animals. Within organisms, genetic information generally is carried in chromosomes, where it is represented in the chemical structure of particular DNA molecules.

Closely-Related Fields

The science which grew out of the union of biochemistry and genetics is widely known as molecular biology. The term "genetics" is often widely conflated with the notion of genetic engineering, where the DNA of an organism is modified for some kind of practical end, but most research in genetics is aimed at understanding and explaining the effect of genes on phenotypes and in the role of genes in populations (see population genetics), rather than genetic engineering. A more recent development is the rise of genomics, which attempts the study of large-scale genetic patterns across the genome for (and in principle, all the DNA in) a given species.

The study of inherited features not strictly associated with changes in the DNA sequence is called epigenetics.

Some take the view that life can be defined, in molecular terms, as the set of strategies which RNA polynucleotides have used and continue to use to perpetuate themselves. This definition grows out of work on the origin of life, specifically the RNA world hypothesis.

Brief History

It wasn't until 1865 that Gregor Mendel first traced inheritance patterns of certain traits in pea plants and showed that they obeyed simple statistical rules. Although not all features show this Mendelian inheritance, his work acted as a proof that application of statistics to inheritance could be highly useful. Since that time many more complex forms of inheritance have been demonstrated.

From his statistical analysis Mendel defined a concept that he described as an allele, which was the fundamental unit of heredity. The term allele as Mendel used it is nearly synonymous with the term gene, whilst the term allele now means a specific variant of a particular gene.

The significance of Mendel's work was not understood until early in the twentieth century, after his death, when his research was re-discovered by other scientists working on similar problems.

Mendel was unaware of the physical nature of the gene. We now know that genetic information is normally carried on DNA. (Certain viruses store their genetic information in RNA). Manipulation of DNA can in turn alter the inheritance and features of various organisms.

Genes encode the information necessary for synthesizing proteins, which, in turn play a large role in influencing, although do not completely determine, the final phenotype of the organism.

Timeline of Notable Discoveries in Genetics

1859 Charles Darwin publishes The Origin of Species
1865 Gregor Mendel's paper, Experiments on Plant Hybridization
1903 Chromosomes are discovered to be hereditary units
1905 British biologist William Bateson coins the term "genetics" in a letter to Adam Sedgwick
1910 Chromosomes include genes
1913 Gene maps show chromosomes containing linear arranged genes
1927 Physical changes in genes are called mutations
1928 Frederick Griffith discoveres a hereditary molecule that is transmissible between bacteria (see Griffiths experiment)
1931 Crossing over is the cause of recombination
1944 Oswald Theodore Avery, Colin McLeod and Maclyn McCarty isolate DNA as the genetic material (at that time called transforming principle)
1945 Genes code for proteins; see the original central dogma of genetics
1950 Erwin Chargaff shows that the four nucleotides are not present in nucleic acids in stable proportions, but that some general rules appear to hold (e.g., that the amount of adenine, A, tends to be equal to that of thymine, T).
1952 The Hershey-Chase experiment proves the genetic information of phages (and all other organisms) to be DNA
1953 DNA structure is resolved to be a double helix by James Watson and Francis Crick
1958 The Meselson-Stahl experiment demonstrates that DNA is semiconservatively replicated
1961 The genetic code is arranged in triplets
1977 DNA is sequenced
1997 First genome sequenced
2001 First draft sequences of the human genome are released simultaneously by the Human Genome Project and Celera Genomics.
2003 (14 April) Successful completion of Human Genome Project with 99% of the genome sequenced to a 99.99% accuracy

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Resources

DOEgenomes.org
Site of the U.S. Human Genome Project, Genomics:GTL Program, and Microbial Genome Program--all sponsored by the U.S. Department of Energy Genome Programs.

Human Genome Project Information
The main homepage for Human Genome Project information --what the project is; its progress, history, and goals; what issues are associated with genome research; frequently asked questions, the science behind the project; who its sponsors are..

American Society of Human Genetics - Home Page
Primary professional membership organization for human geneticists in North America.

The American Journal of Human Genetics
Since its inception in 1948, AJHG has provided a record of research and review relating to heredity and human genetics.

ESHG Home Page
Promotes research in basic and applied human and medical genetics.

WTCHG
UK centre for the study of the genetics of multifactorial diseases such as hypertension, diabetes,...

Welcome to the Human Genetics Commission website
UK Government site concerning the implications of recent developments in the science of genetics.

Human Genetics Society of Australasia
Promote standards, research, and education.

IFHGS International Federation of Human Genetics Societies
Provides a forum for organized groups including research, clinical practice, and professional.

MRC HGU - Medical Research Council Human Genetics Unit
Undertakes research to obtain a molecular and cellular understanding of genetic factors.

Eccles Institute of Human Genetics
Features graduate program and current faculty research interests in areas of human genetics.

HUM-MOLGEN - International Communication Forum in Human Molecular ...
Features a mailing list, table of contents of leading journals, listings of meetings and seminars.

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