<unk>  is a branch of biology concerned with the study of<unk> es,<unk> variation, and heredity in organisms. Though heredity had been observed for millennia, Gregor Mendel, Moravian scientist and Augustinian friar working in the 19th century in Brno, was the first to study<unk>  scientifically. Mendel studied "trait inheritance", patterns in the way traits are handed down from parents to offspring over time. He observed that organisms (pea plants) inherit traits by way of discrete "units of inheritance". This term, still used today, is a somewhat ambiguous definition of what is referred to as a<unk> e. Trait inheritance and molecular inheritance mechanisms of<unk> es are still primary principles of<unk>  in the 21st century, but modern<unk>  has expanded beyond inheritance to studying the function and behavior of<unk> es.<unk> e structure and function, variation, and distribution are studied within the context of the cell, the organism (e.g. dominance), and within the context of a population.<unk>  has given rise to a number of subfields, including molecular<unk> , epigenetics and population<unk> . Organisms studied within the broad field span the domains of life (archaea, bacteria, and eukarya).<unk> processes work in combination with an organism's environment and experiences to influence development and behavior, often referred to as nature versus nurture. The intracellular or extracellular environment of a living cell or organism may switch<unk> e transcription on or off. A classic example is two seeds of<unk> lly identical corn, one placed in a temperate climate and one in an arid climate (lacking sufficient waterfall or rain). While the average height of the two corn stalks may be<unk> lly determined to be equal, the one in the arid climate only grows to half the height of the one in the temperate climate due to lack of water and nutrients in its environment.
Genetics
Cell biology
Molecular medicine
Nuclear technology
Developmental biology
RNA Biology
Molecular neuroscience
Reproductive immunology