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In its 1993 decision Daubert v. Merrell Dow Pharmaceuticals, Inc., the US Supreme Court established the Daubert Standard for evaluating the admissibility of scientific knowledge as evidence in US federal courts. When it began in trial court, the case addressed whether or not Bendectin, an anti-nausea medication taken during pregnancy, caused birth defects. However, after the trial court dismissed the case for lack of admissible evidence, Daubert v. Merrell Dow Pharmaceuticals, Inc.
Twentieth-century researcher Ernest John Christopher Polge studied the reproductive processes of livestock and determined a method to successfully freeze, thaw, and utilize viable sperm cells to produce offspring in animals. In 1949, Polge identified glycerol as a cryoprotectant, or a medium that enables cells to freeze without damaging their cellular components or functions. Several years later, Polge used glycerol in a freezing process called vitrification, which enabled him to freeze poultry sperm, thaw that sperm, and use it to fertilize vertebrate embryos.
Mitochondrial DNA (mtDNA) is located outside the nucleus in the liquid portion of the cell (cytoplasm) inside cellular organelles called Mitochondria. Mitochondria are located in all complex or eukaryotic cells, including plant, animal, fungi, and single celled protists, which contain their own mtDNA genome. In animals with a backbone, or vertebrates, mtDNA is a double stranded, circular molecule that forms a circular genome, which ranges in size from sixteen to eighteen kilo-base pairs, depending on species. Each mitochondrion in a cell can have multiple copies of the mtDNA genome.
The Y-chromosome is one of a pair of chromosomes that determine the genetic sex of individuals in mammals, some insects, and some plants. In the nineteenth and twentieth centuries, the development of new microscopic and molecular techniques, including DNA sequencing, enabled scientists to confirm the hypothesis that chromosomes determine the sex of developing organisms. In an adult organism, the genes on the Y-chromosome help produce the male gamete, the sperm cell. Beginning in the 1980s, many studies of human populations used the Y-chromosome gene sequences to trace paternal lineages.