Nuclear DNA

Source: Wikipedia, the free encyclopedia.

Nuclear DNA (nDNA), or nuclear deoxyribonucleic acid, is the

matrilineally (through the mother) as in mitochondrial DNA.[2]


Nuclear DNA is a

nucleotides.[3] Each nucleotide is composed of a five-carbon sugar, a phosphate group, and an organic base. Nucleotides are distinguished by their bases: purines, large bases that include adenine and guanine; and pyrimidines, small bases that include thymine and cytosine. Chargaff's rules state that adenine always pairs with thymine, and guanine always with cytosine. The phosphate groups are held together by a phosphodiester bond and the bases are held together by hydrogen bonds.[4]

Differences to mitochondrial DNA

Nuclear DNA and

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.[6]


Nuclear DNA is known as the molecule of life and contains the genetic instructions for the development of all eukaryotic 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.[7] 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).[8][9]

Cell division


would result in offspring with twice the normal number of chromosomes.

Meiosis creates new combinations of genetic material in each of the four daughter cells. These new combinations result from the exchange of DNA between paired chromosomes. Such an exchange means that the gametes produced through meiosis often exhibit considerable genetic variation.

Meiosis involves two rounds of nuclear division, not just one. Prior to undergoing meiosis, a cell goes through an interphase period in which it grows, replicates its chromosomes, and checks all of its systems to ensure that it is ready to divide.

Like mitosis, meiosis also has distinct stages called prophase, metaphase, anaphase, and telophase. A key difference, however, is that during meiosis, each of these phases occurs twice — once during the first round of division, called meiosis I, and again during the second round of division, called meiosis II.[10]


Prior to cell division, the DNA material in the original cell must be duplicated so that after cell division, each new cell contains the full amount of DNA material. The process of DNA duplication is usually called

semiconservative since each new cell contains one strand of original DNA and one newly synthesized strand of DNA. The original polynucleotide strand of DNA serves as a template to guide the synthesis of the new complementary polynucleotide of DNA. The DNA single-strand template serves to guide the synthesis of a complementary strand of DNA.[11]

DNA replication begins at a specific site in the DNA molecule called the

Okazaki fragments. Each Okazaki fragment requires a separate RNA primer. As the Okazaki fragments are synthesized, the RNA primers are replaced with DNA nucleotides and the fragments are bonded together in a continuous complementary strand.[12]

DNA damage and repair


Nuclear DNA is subject to mutation. A major cause of mutation is inaccurate DNA replication, often by specialized DNA polymerases that synthesize past DNA damages in the template strand (error-prone trans-lesion synthesis).[16] Mutations also arise by inaccurate DNA repair. The microhomology-mediated end joining pathway for repair of double-strand breaks is particularly prone to mutation.[17] Mutations arising in the nuclear DNA of the germline are most often neutral or adaptively disadvantageous. However, the small proportion of mutations that prove to be advantageous provide the genetic variation upon which natural selection operates to generate new adaptations.


See also


  1. ^ "DNA" – via The Free Dictionary.
  2. ^ "* Nuclear genome (Biology) - Definition, meaning - Online Encyclopedia".
  3. ^ "Nuclear DNA".
  4. ^ "DNA: The Genetic Material". Archived from the original on 2020-11-09. Retrieved 2013-03-19.
  5. S2CID 4355527
  6. ^ "Mitochondrial DNA". Archived from the original on 2014-02-01. Retrieved 2014-04-23.
  7. ^ Casselman, Anne. "Identical Twins' Genes Are Not Identical". Scientific American. Retrieved 18 January 2014.
  8. ^ "Forensic Science - Nuclear DNA".
  9. ^ "FBI — Nuclear-DNA Unit". Archived from the original on 2014-07-01. Retrieved 2016-07-28.
  10. ^ "Replication and Distribution of DNA during Meiosis | Learn Science at Scitable".
  11. ^ "DNA Replication". Archived from the original on 2013-01-28. Retrieved 2013-04-02.
  12. ^ "DNA Replication".
  13. PMID 21600302
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