Nuclear DNA

Nuclear DNA (nDNA), or nuclear deoxyribonucleic acid, is the DNA contained within each cell nucleus of a eukaryotic organism. Nuclear DNA encodes for the majority of the genome in eukaryotes, with mitochondrial DNA and plastid DNA coding for the rest. Nuclear DNA adheres to Mendelian inheritance, with information coming from two parents, one male and one female, rather than matrilineally (through the mother) as in mitochondrial DNA. Nuclear DNA (nDNA), or nuclear deoxyribonucleic acid, is the DNA contained within each cell nucleus of a eukaryotic organism. Nuclear DNA encodes for the majority of the genome in eukaryotes, with mitochondrial DNA and plastid DNA coding for the rest. Nuclear DNA adheres to Mendelian inheritance, with information coming from two parents, one male and one female, rather than matrilineally (through the mother) as in mitochondrial DNA. Nuclear DNA is a nucleic acid, a polymeric biomolecule or biopolymer, found in the nucleus of eukaryotic organisms. Its structure is a double helix, with two strands wound around each other. This double helix structure was first described by Francis Crick and James D. Watson (1953) using data collected by Rosalind Franklin. Each strand is a long polymer chain of repeating nucleotides. Each nucleotide is composed of a five-carbon sugar, a phosphate group, and an organic base. Nucleotides are distinguished by their bases. There are the purines, large bases which include adenine and guanine, and pyrimidines, small bases which include thymine and cytosine. Chargaff's rules state that adenine will always pair with thymine and guanine will always pair with cytosine. The phosphate groups are held together by a phosphodiester bond and the bases are held together by hydrogen bonds. Nuclear DNA and mitochondrial DNA differ in many ways, starting with location and structure. Nuclear DNA is located within the nucleus of eukaryote cells and usually has two copies per cell while mitochondrial DNA is located in the mitochondria and contains 100-1,000 copies per cell. The structure of nuclear DNA chromosomes is linear with open ends and includes 46 chromosomes containing 3 billion nucleotides. Mitochondrial DNA chromosomes usually have closed, circular structures, and contain for example 16,569 nucleotides in human. Nuclear DNA is diploid, ordinarily inheriting the DNA from two parents, while mitochondrial DNA is haploid, coming only from the mother. The mutation rate for nuclear DNA is less than 0.3% while that of mitochondrial DNA is generally higher. Nuclear DNA is known as the molecule of life and contains the genetic instructions for the development of all living organisms. It is found in almost every cell in the human body, with exceptions such as red blood cells. Everyone has a unique genetic blueprint, even identical twins. Forensic departments such as the Bureau of Criminal Apprehension (BCA) and Federal Bureau of Investigation (FBI) are able to use techniques involving nuclear DNA to compare samples in a case. Techniques used include polymerase chain reaction (PCR), which allows one to utilize very small amounts of DNA by making copies of targeted regions on the molecule, also known as short tandem repeats (STRs). Like mitosis, meiosis is a form of eukaryotic cell division. Meiosis gives rise to four unique daughter cells, each of which has half the number of chromosomes as the parent cell. Because meiosis creates cells that are destined to become gametes (or reproductive cells), this reduction in chromosome number is critical — without it, the union of two gametes during fertilization would result in offspring with twice the normal number of chromosomes.