Nucleic acid hybridization natural positions within a chromosome). In 1969, the two scientists published a paper demonstrating that radioactive copies of a ribosomal DNA sequence could be used to detect complementary DNA sequences in the nucleus of a frog egg. Since those original observations, many refinements have increased the versatility and sensitivity of the procedure to the extent that in situ hybridization is now considered an essential tool in cytogenetics. Nucleic acid hybridization In molecular biology, hybridization (or hybridisation) is a phenomenon in which single-stranded deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) molecules anneal to complementary DNA or RNA. Though a double-stranded DNA
Petroselinic acid in Garryaceae. In Picramniaceae, petroselinic acid is accompanied by tariric acid. In addition, petroselinic acid has been found in minor amounts in several fats of plant and animal origin, including in human sources. The occurrence of petroselinic acid as the major fatty acid is used in chemosystematics as a proof of a close relationship of several families within the Apiales as well as within the Garryales. Besides petroselinic acid, oleic acid has been shown to be present in all cases examined. Fatty acids mostly occur as their esters, commonly the triglycerides, which are the greasy materials in many natural oils.