There are 5 known Prokaryotic DNA polymerases:
There are at least 15 Eukaryotic DNA polymerase:
Family B
Polymerases mostly contain replicative polymerases and include the major eukaryotic DNA polymerases α, δ, ε, (see Greek letters) and also DNA polymerase ζ. Family B also includes DNA polymerases encoded by some bacteria and bacteriophages, of which the best-characterized are from T4, Phi29, and RB69 bacteriophages. These enzymes are involved in both leading and lagging strand synthesis during replication. A hallmark of the B family of polymerases is their highly faithful DNA synthesis during replication. While many have an intrinsic 3'-5' proofreading exonuclease activity, eukaryotic DNA polymerases α and ζ are two examples of B family polymerases lacking this proofreading activity.
Family_C">Family CPolymerases are the primary bacterial chromosomal replicative enzymes. DNA Polymerase III alpha subunit from E. coli is the catalytic subunit [1] and possesses no known nuclease activity. A separate subunit, the epsilon subunit, possesses the 3'-5' exonuclease activity used for editing during chromosomal replication. Recent research has classified Family C polymerases as a subcategory of Family X[citation needed]. Family_D">Family DPolymerases are still not very well characterized. All known examples are found in the Euryarchaeota subdomain of Archaea and are thought to be replicative polymerases. Family_X">Family XContains the well-known eukaryotic polymerase pol β, as well as other eukaryotic polymerases such as pol σ, pol λ, pol μ, and terminal deoxynucleotidyl transferase (TdT). Pol β is required for short-patch base excision repair, a DNA repair pathway that is essential for repairing abasic sites. Pol λ and Pol μ are involved in non-homologous end-joining, a mechanism for rejoining DNA double-strand breaks. TdT is expressed only in lymphoid tissue, and adds "n nucleotides" to double-strand breaks formed during V(D)J recombination to promote immunological diversity. The yeast Saccharomyces cerevisiae has only one Pol X polymerase, Pol IV, which is involved in non-homologous end-joining. Family_Y">Family YY Polymerases differ from others in having a low fidelity on undamaged templates and in their ability to replicate through damaged DNA. Members of this family are hence called translesion synthesis (TLS) polymerases. Depending on the lesion, TLS polymerases can bypass the damage in an error-free or error-prone fashion, the latter resulting in elevated mutagenesis. Xeroderma pigmentosum variant (XPV) patients for instance have mutations in the gene encoding Pol η (eta), which is error-free for UV-lesions. In XPV patients, alternative error-prone polymerases, e.g., Pol ζ (zeta) (polymerase ζ is a B Family polymerase a complex of the catalytic subunit REV3L with Rev7, which associates with Rev1[2]), are thought to be involved in mistakes that result in the cancer predisposition of these patients. Other members in humans are Pol ι (iota), Pol κ (kappa), and Rev1 (terminal deoxycytidyl transferase). In E. coli, two TLS polymerases, Pol IV (DINB) and Pol V (UmuD'2C), are known.Family RT
The reverse transcriptase family contains examples from both retroviruses and eukaryotic polymerases. The eukaryotic polymerases are usually restricted to telomerases. These polymerases use an RNA template to synthesize the DNA strand.
Variety across Species:DNA polymerases have highly-conserved structure, which means that their overall catalytic subunits vary, on a whole, very little from species to species. Conserved structures usually indicate important, irreplaceable functions of the cell, the maintenance of which provides evolutionary advantages.Some viruses also encode special DNA polymerases, such as Hepatitis B virus DNA polymerase. These may selectively replicate viral DNA through a variety of mechanisms. Retroviruses encode an unusual DNA polymerase called reverse transcriptase, which is an RNA-dependent DNA polymerase (RdDp). It polymerizes DNA from a template of RNA.
yes. rare disease saw on the discovery channel.
Add infoThe rare disease is Chimerism.Chimerism is not a disease, but a genetic mutation that can occur where fraternal twins, which have different and separate DNA have offspring that may exhibit both sets of the DNA. For example, DNA taken from hair may show a different sequence than that taken from the mouth, and this from the same individual!
There are four types DNA namely A, B, Z and C of which B DNA is commonest.
Every human has the same DNA but the chemical that make the DNA are just in a different order.
Every human has the same DNA but the chemical that make the DNA are just in a different order.
three
millions of different types of T cells
It has about 200 cells. I'm 11
1
There are several. Deserts, for example, exist in many latiitudes.
There is roughly around 200 different types of cells in your body.
There are over 200 different types of cells are in your body.
three
millions of different types of T cells
there are 3 different types: capillaries, veins, and arteries
Over a thousand.
there are different types of baboons. they also live in different parts of the world. many are found in Africa
The human body has 4 primary tissue types: epithelium, connective tissue, nervous tissue, and muscle.
It has about 200 cells. I'm 11
There are three types of blood vessels. There are veins, arteries, and capillaries.
There are over 200 types of cancer. There are over 60 organs where cancer can form in your body. Cancer can form in about all types of cells in your body.
There are many types of gekko that exist. Worldwide, there are over one thousand and five hundred different species that can be found in all different countries.