DNA Double Helix Models
The Indigo® 12 base pair DNA model, first shown at NABT 1996, costs only $329.00 & can build 262,144 different base-pair sequences. Even if you need the odd replacement part that works out to <$0.01 per student-lab! Or, build just AT & GC base pairs for $16.25 each.
Be the envy of all. The Indigo® Big Bang Theory DNA Model has 36 base pairs, stands ~2m (6') tall & has 18 quadrillion (1.8x1016 possible sequences). Get yours with its unique sequence while supplies last.
Explore more options below including two custom Indigo® alpha helix models designed to fit the major grooves of our 12/17/36 base pair DNA models.
DNA Overview
Deoxyribonucleic acid (DNA) the ultimate information database, is the library of life’s blueprints. It constitutes the genetic code with all the instructions needed to produce & sustain virtually every lifeform on Earth.
DNA’s structure is both simple & complex at the same time. It is made up of only 5 of the 94 naturally occurring elements in the periodic table. Yet when carbon, hydrogen, nitrogen, oxygen & phosphorus are combined into the billions of base sequences found in a typical genome, they account for life's inestimable diversity. Collectively, DNA & RNA are nucleic acids, one of 4 fundamental building blocks which includes proteins (amino acids), lipids (fatty acids) and carbohydrates (sugars & related compounds).
Knowing how these elements are put together is essential to understanding how the entire process works. This impacts our health benefits, reveals our ancestry and can even identify criminals. Simply viewing nucleotide sequences like ATCGGCATA… on a computer screen is not enough. Physical molecular models can help with the big picture.
DNA Nitrogenous Bases
The overall chemical structure of the DNA molecule is a polymer, consisting of two strands of polynucleotides, in turn made up of individual nucleotide monomers. The monomer building blocks are nitrogenous bases also known as nucleosides which come in 2 forms, purines & pyrimidines.
The pyrimidines, thymine, cytosine & uracil (in RNA only), are hexagonal (6-sided structures) rings. The purines, adenine & thyme are polycyclic rings (6 sides and 5 sides) that share a common side.
Each purine aligns with one corresponding pyrimidine to form a base pair. These are denoted AT & GC which when connected, create the base sequence which is the essence of the DNA structure. To this end, we offer DNA models in 3 styles with the base pairs shown immediately below.
Orbit Style
Features:
- 12 base pairs, 6 each AT & GC
- 1 turn; ~1m (3') tall
- Repeat assembly lab exercise
- Major/minor grooves to scale
- Skeletal-ball & stick
- Discrete double bonds
- No discrete H atoms
- Optional alpha helix model
- High school through university
Molymod Style
Features:
- 17 or 36 base pair versions
- 1.5 or 3 turns; 1 or 2m (3 or 6')
- Comes assembled only
- Major/minor grooves to scale
- Semi-spacefilling style
- Double bonds implied
- Discrete hydrogen atoms
- Optional alpha helix model
- High school through university
- School, museum, corporate display
Molymod "Mini DNA" Style
Features:
- 22 base pairs, 11 each AT & GC
- Color coded bases, cannot mismatch
- 2 turns, 45cm tall
- No discrete atoms
- No discrete bonds
- Needs assembly
- Major/minor grooves, not to scale
- Suitable for beginners
Deoxyribose Phosphates
Deoxyribose phosphate groups form the backbone of the DNA polymer. They are connected to each other via phosphodiester bonds between carbons designated 3' & 5'. These carbons are arranged antiparallel facing 3'-5' in one spiral & 5'-3' in the other. Antiparallel means one side of the sugar phosphates chain 3’ spirals upwards, the other side has 3’ chain spiralling downwards. The 1' carbons of the sugar rings are in turn connected to the N9 (nitrogen ) position of the purine rings and N1 (nitrogen) position of the pyrimidine rings.
We offer stand alone models of ribose & deoxyribose so you can show the differences in structure of deoxyribose nucleic acid & ribonucleic acid. See below for examples.
Image from Review of the Universe,DNA: universe-review.ca
Orbit Style
Molymod Style
Features:
- Discrete covalent bonds
- Discrete hydrogen atoms
- Semi-spacefilling
Molymod "Mini DNA" Style
Features:
- Red pentagon for deoxyribose
- Purple pyramid for phosphate
- No discrete atoms or bonds
DNA Double Helix Models
We offer 3 styles of DNA model each consisting of the 3 components that make up the monomer subunits of the DNA polymer. These are the nitrogenous base (nucleobase), a pentose sugar and a phosphate group. Each model style has its merits depending cost & how the model is to be used.
A fundamental feature of the B-DNA double helix is its major & minor grooves. These are formed by the asymmetry of the antiparallel helices. The 12/17/36 base pair models closely approximate the differences in their widths, 2.2nm vs 1.2nm for the major & minor grooves respectively. This aspect of the double helix structure is especially important as it illustrates why processes such as transcription are usually restricted to the major groove. This is further demonstrated by our complementary alpha helix models which easily fit the major but not the minor groove.
12 Base Pair DNA Model
The 12 base pair model is our best teaching model. It was designed with the intent of assembly & reassembly by successive groups of students. We estimate that when used as an educational tool, the cost is $0.15 per student over the lifetime of the model.
The kit comes with 6 AT & 6 GC pairs which can be combined to show 262144 different DNA sequences. This alone makes it useful for illustrating the importance of species diversity. It also unique among models in having both common VSEPR geometries for carbon & nitrogen, as well as uncommon ones, to accurately build the conjoined polycyclic (5 & 6 member) purine rings.
2 important shortcuts are used to make this a practical teaching tool. Hydrogen atoms are not included since they do not contribute to the overall understanding of the structure. This helps reduce the cost of the model as well as eliminates unnecessary assembly time. Hydrogen bonds between complementary nucleotide bases are stylized for simplicity. All single and double covalent bonds are explicit and are used to make the antiparallel nature of the double helices obvious and assist in spotting final assembly errors.
17 & 36 Base Pair DNA Models
The 17 & 36 base pair models are our most elegant and most versatile. They have been used in classrooms, TED lectures, presidential speeches & courtroom patent disputes. Some are on display in major biotech companies and still others have been gifted to retiring professors & benefactors. Arguably our most famous, it is also featured in the Big Bang Theory TV show.
These models show all the important structural features from base pair complementarity to accurately depicting major & minor grooves. The elements are color coded according to the standard scheme. Carbon is black, nitrogen is blue, oxygen is red, phosphorus is purple and both univalent and divalent linear hydrogens are white. The model style is semispacefilling, also referred to as "closed dome" with double bonds implied. This produces flattened rings which are firmly fixed to their respective plastic layers.
The 17 & 36 base models are made as chemically accurate as possible with multiple customizations. As such, they are only available assembled.
22 Base Pair Mini DNA Model
The miniDNA model is the simplest model to assemble & comes with a short set of instructions. The 6 different colors differentiate the 4 bases, deoxyribose & phosphate. It only allows bonding between adenine & thymine and guanine & cytosine ensuring base pair complementarity is straightforward. An individual should be able to build it under an hour.
