Genetics

Genetics is that branch of science which relates to the study of genes, and their role in [biological inheritance]?. This is the process by which offspring tend to have features similar to their parents. The earliest applications of genetics were developed long before the beginning of recorded history, with the domestication? and [selective breeding]? of plants and animals.

It wasn't until 1865 that Gregor Mendel first traced [inheritance pattern]?s 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 example 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 they are the information normally carried on DNA. Manipulation of the DNA can in turn alter the inheritance, and features of various organisms. This science which grew out of biochemistry and genetics is widely known as molecular biology.

Timeline:

1865 Gregor Mendel

1903 Chromosomes are discovered to be hereditary units

1910 Chromosomes include genes

1913 [Gene map]?s show chromosomes containing linear arranged genes

1927 Physical changes in genes are called mutations

1931 [Crossing over]? is the cause of recombination?

1944 Avery? isolates DNA as the genetic material (at that time called [transforming principle]?)

1945 Genes code for proteins; see the original central dogma of genetics

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?

1958 DNA is semiconservatively replicated

1961 The genetic code is arranged in triplets

1977 DNA is sequenced?

1997 First genome sequenced

2001 Human genome is sequenced by the Human Genome Projects

The study of inherited features not strictly associated with DNA is called epigenetics?.

See also : biology -- central dogma of genetics