Galifreyan and Trantorian Supercoiled Triple Helix H-DNA and Polyploidity. 1

 Galifreyan and Trantorian Supercoiled Triple Helix H-DNA and Polyploidity.

1. Galifreyan and Trantorian Triple Helix

2. Polyploidity

 

1. Galifreyan and Trantorian Triple Helix

Like Galifreyans, native Trantorian genetic structures have what is known as Supercoiled DNA, specifically triple helical DNA, known as H-DNA, instead of the more common B-DNA for double helix DNA.

Supercoiled triple helical H-DNA is more common among three-gendered reproductive species than it is among two-gendered reproductive species.

Triple-stranded DNA (also known as H-DNA or Triplex-DNA) is a DNA structure in which three oligonucleotides wind around each other and form a triple helix. In triple-stranded DNA, the third strand binds to a B-form DNA double helix by forming Hoogsteen base pairs or reversed Hoogsteen hydrogen bonds, hence the term H-DNA.

Synthetic triplex forming oligonucleotides (TFO) have been experimented with for their possible pharmaceutical roles.

A DNA triplex is formed when pyrimidine or purine bases occupy the major groove of the DNA double Helix forming Hoogsteen pairs with purines of the Watson-Crick basepairs. Intermolecular triplexes are formed between triplex forming oligonucleotides (TFO) and target sequences on duplex DNA. Intramolecular triplexes are the major elements of H-DNAs, unusual DNA structures, which are formed in homopurine-homopyrimidine regions of supercoiled DNAs. TFOs are promising gene-drugs, which can be used in an anti-gene strategy, that attempt to modulate gene activity in vivo. Numerous chemical modifications of TFO are known. In peptide nucleic acid (PNA), the sugarphosphate backbone is replaced with a protein-like backbone. PNAs form P-loops while interacting with duplex DNA fonning triplex with one of DNA strands leaving the other strand displaced. Very unusual recombination or parallel triplexes, or R-DNA, have been assumed to form under RecA protein in the course of homologous recombination

The most obvious result in Supercoiled triple helical H-DNA on the organism level is a vast decrease in the mutation rate and the long generational stability of the genome. With three bases at each location it would be necessary to mutate two of them simultaneously in order for a change to be kept. The obverse of this is a vast decrease in the evolution of said organisms.

The Evolutionary Stagnation of Galifreyans and Trantorians is well known, as their resistance to cancers and other genetic damaging maladies.

Supercoiled triple helical H-DNA has many advantages for gene therapies.

The triple helical structure provides strength and stability to collagen fibers by providing great resistance to tensile stress. The rigidity of the collagen fibers is an important factor that can withstand most mechanical stress, making it an ideal protein for macromolecular transport and overall structural support throughout the body.

There are some oligonucleotide sequences, called triplet-forming oligonucleotides (TFOs) that can bind to form a triplex with a longer molecule of double-stranded DNA; TFOs can inactivate a gene or help to induce mutations for gene-editing. TFOs can only bind to certain sites in a larger molecule, so researchers must first determine whether a TFO can bind to the gene of interest.

Supercoiled triple helical H-RNA has become more studied. Some roles include increasing stability, translation, influencing ligand binding, and catalysis. One example of ligand binding being influenced by a triple helix is in the SAM-II riboswitch where the triple helix creates a binding site that will uniquely accept S-adenosylmethionine (SAM). The ribonucleoprotein complex telomerase, responsible for replicating the tail-ends of DNA (telomeres) also contains triplex RNA believed to be necessary for proper telomerase functioning. The triple helix at the 3' end of MALAT1 serves to stabilize the RNA by protecting the Poly-A tail from proteolysis as well as increases translation efficiency, which is ultimately detrimental to humans as MALAT1 is related to lung cancer malignancy.

Triple Helixes occur naturally in the Humani genome in about 2-3% of pregnancies and about 15% of miscarriages. This is roughly equivalent to the very low interfertility rate and very high miscarriage rate between Galifreyans and Trantorians with double helixed Humani. The few surviving intermixings result in the triple helix being carried forward to the next generation, most reverting back to the base B-DNA double helixed genome, most of the genetic heritage of the Galifreyan or Trantorian parent being lost.

 

2. Polyploidity.

The triple-helix H-DNA of native Galifreyans and Trantorians is not to be confused with the polyploidity common to their native animal and plant species, having more than two paired homologous sets of chromosomes. Galifreyan and Trantorian polyploidity may have been what allowed the evolutionary progress of Galifreyans and Trantorians despite the stagnating effects of their triple helix genetic structure.

One evolutionary advantage to polyploidy is that a mutation in one copy of a gene can be hidden by a functioning gene in the other genome. This creates variation that may later have an advantage if the environmental conditions change. Thus, polyploidy buffers against deleterious mutations, but by allowing them to happen, winds up increasing the variation of genes in the organism that may prove beneficial later.

The prolific colonization projects of the early millennia of the Trantorian Imperium, spread many Trantorian plant species to innumerable planets. The polyploidity of Trantorian flora made them easily adaptable to a wide variety of planetary conditions, making early Trantorians very successful colonists. Trantorian sourced flora and fauna are virtually ubiquitous throughout the Mutter’s Spiral Galaxy

The most common domesticated crops such as wheat, corn, oats, rye, barley, sugar cane, potato, canola, sunflower, rice, cotton, peanuts, cannabis, tobacco, ginger, Arabica coffee, black mulberry, apples, pineapple, most citris, some onion and garlic varieties, most brassica (broccoli, caulifrower, mustard, cabbages, turnips, rutabaga, arugula, horseradish), seedless watermelon, eucalyptus trees, strawberries, bananas, and kiwi fruit are all polyploid, which aided in their adaptability to different cultivation condition and also aided in their hybridization, and making grafting possible for many fruit and nut tree varieties.

In addition to being more adaptable to varying environmental conditions, polyploid species are more easily hybridized partly at least because they suffer from less inbreeding depression.

Hibiscus, saffron crocus, tulips, and lilies are also poplyploid.

The yeasts used for baking, and the fermentation of beer and wines are also poplyploid.

The Agrodiaetus butterfly is thought to be of Trantorian origin.

Salmon, koi goldfish, and sturgeon are also polyloid, and thought to be of Trantorian origin.

The marbled crayfish or Marmorkrebs is also a triploid species, but only reproduces asexually by parthenogenesis.

The octodontin rodent, Argentine desert plains vischacha rat (Tympanoctomys barrerae) is a tetraploid chinchilla-kin type species that is thought to be of Trantorian origin.

Polyploid (triploid) mole salamanders are all female and reproduce by kleptogenesis, "stealing" spermatophores from diploid males of near related species to trigger egg development but not incorporating the males' DNA into the offspring.

Paleopolyploidy is dated back to the origins of angiosperms (flowering plants) from around 160 million years ago and is considered one of the two major primordial Ossian polyploid terraforma projects.

The Xenopus (frog), Fugu (pufferfish), zebrafish, salmon, and lampreys also are the result of ancient paleopolyploid events.

Many Paleopolyploid species revert to being diploid thru a process known as diploidization, mostly from selective pressure due to redundant genes. Those with more non-redundant genes maintain their polyploidy genetics.

 

(Thank you to Professor Serendipity, Mirra Zanzibar, and Mercedes Celestalis for the source materials)