The history of genetics is
generally held to have started with the work of an,
Gregory Mendel. His work
on pea plants, published in 1866, described what came to be known as Mendel
Ian Inheritance. In the centuries before—and for several decades
after—Mendel's work, a wide variety of theories of heredity proliferated
.1900 marked the "rediscovery of Mendel". Alongside experimental work,
mathematicians developed the statistical framework of population genetics,
bring genetically explanations into the study of evolution.
With the basic patterns of genetic inheritance established, many biologists turned to investigations of the physical nature of the gene. In the 1940s and early 1950s, experiments pointed to DNA as the portion of chromosomes that held genes. A focus on new model organisms such as viruses and bacteria, along with the discovery of the double helical structure of DNA in 1953, marked the transition to the era of molecular genetics. In the following years, chemists developed techniques for sequencing both nucleic acids and proteins, while others worked out the relationship between the two forms of biological molecules: the genetic code. The regulation of gene expression became a central issue in the 1960s; by the 1970s gene expression could be controlled and manipulated through genetic engineering. In the last decades of the 20th century, many biologists focused on large-scale genetics projects, sequencing entire genomes.
What is Genetics???
Genetics, a discipline of
biology, is the science of heredity and variation in living organisms. The
fact that living things inherit traits from their parents has been used
since prehistoric times to improve crop plants and animals through selective
breeding. However, the modern science of genetics, which seeks to understand
the process of inheritance, only began with the work of Greg or Mendel in
the mid-nineteenth century. Although he did not know the physical basis for
heredity, Mendel observed that organisms inherit traits in a discrete
manner—these basic units of inheritance are now called genes.
Genes correspond to regions within DNA, a molecule composed of a chain of four different types of nucleotides—the sequence of these nucleotides is the genetic information organisms inherit. DNA naturally occurs in a double stranded form, with nucleotides on each strand complementary to each other. Each strand can act as a template for creating a new partner strand—this is the physical method for making copies of genes that can be inherited.