Gene-Seed

The gene-seed of an Adeptus Astartes Space Marine is the foreign genetic material originally engineered using one of the Primarchs' genomes as a foundation that develops into the special organs that are then implanted into a potential Space Marine's body. These organs created from the gene-seed are responsible for most of a Space Marine's physical enhancements over baseline human capability. All Space Marine gene-seed was originally cultivated by the Emperor himself from the DNA of the Emperor's 20 genetically-engineered sons (each son being the Primarch of one of the 20 Space Marine Legions of the First Founding), and is a rare and precious resource for the Space Marines of the Imperium, even in death. The biotechnology necessary to create new gene-seed has long been forgotten or lost to humanity; therefore, it must be cultivated from dead/dying Astartes warriors and returned to the Chapter's Apothecaries who will oversee the creation of new Astartes from the Chapter's raw recruits. The gene-seed is the very essence of a Space Marine Chapter and it carries each of the characteristics that are particularly unique to a given Chapter, be they mental, physical, spiritual, martial, or cultural.

Unfortunately, Space Marine gene-seed is vulnerable to mutations over time, which can phenotypically manifest in various ways. In addition, there are various genetic flaws which have developed in the gene-seed, the majority of which derive from the particularities of each Primarch's genetic code. Hence the flaws in the Blood Angels' gene-seed (specifically their susceptibility to the conditions known as the Black Rage and the Red Thirst), the "Mark of the Wulfen" for the Space Wolves or the rapidly increasing rate of mutation within the Renegade Soul Drinkers Chapter.

It must also be noted that the presently existing Space Marine Chapters are more numerous than the original 20 Space Marine Legions, excluding those Legions that are no longer recorded or were removed from Imperial records. Only the original Legions that remained loyal to the Emperor during the Horus Heresy produced the numerous Space Marine Chapters of the Second Founding who share traits with their founder Chapter, itself the remnant of one of the original Loyalist Legions.

During the recruitment and enhancement process, some recruits may not survive the initial rigours of training and the later medical treatments one must undergo to become a full-fledged Battle-Brother. First and foremost, a potential Space Marine recruit must be male, as the gene-seed and the developing Space Marine organ zygotes are compatible only with male hormones. The three following requirements also apply:

* Space Marine recruits must be adolescents or very young adults, as the implants must be able to coordinate with a human male's natural growth hormones during adolescence to stimulate the growth and development of the various unique physiological features of a Space Marine. In specific terms, the recruit must be about 10-16 Terran standard years of age.

* Much like a blood transfusion or organ transplant, there must be genetic compatibility between the recruit and the implants; otherwise organ failure may result, causing the recruit to die or simply degenerate into a state of madness.

* The mental state of a potential space Marine must also be susceptible to the various training and psycho-conditioning regimes of the Chapter, and cannot be tainted by the Ruinous Powers of Chaos.

These three main criteria bar all except a minuscule percentage of human males within the Imperium of Man from becoming Space Marines. If all the tests prove successful, the potential Space Marine becomes a Neophyte or Scout Marine, depending on the Chapter's individual organization. The recruit is then taken to live at the Chapter's fortress-monastery where he is instructed in the ways of battle and taught the values and history of the Chapter. At this stage, organ implantation, psycho-conditioning, and physical training begin. Each step in this stage has its own dangers, ensuring that only the truly worthy recruits become Space Marines. After several years of training, conditioning, and implantation surgeries the Neophyte becomes a Space Marine, undergoes his Rites of Fire, and becomes a fully-fledged Battle-Brother of his Chapter.

Implantation

Nineteen genetically-engineered organs grown from the Chapter's gene-seed are implanted in a Neophyte's body to further bolster his combat and survival ability should he live to become a Brother-Marine. Each implant has a high margin of catastrophic failure and physiological rejection and so only a small number of Neophytes live to become Initiates. Many Chapters have lost the knowledge needed to create some of these implants, and therefore, must ensure these are recovered from dead Brother-Marines. Amongst the crucial implants are the Black Carapace and the Progenoid Glands, without which, a Chapter would die out fairly quickly.

* Secondary Heart - This is the first and least difficult implant to install. The Secondary Heart increases blood supply and pumping capacity and is capable of taking over entirely should the primary heart fail. It may also pump steroids into the 1st heart to give the Marine an extra "rush" on the battlefield.

* Ossmudula - This implant strengthens the skeleton of a Space Marine by inducing the bones to absorb a ceramic-based substance administered in a Marine's diet. Within two years after the surgery, the Marine's skeleton will be larger and exponentially stronger than a normal man's; and the rib cage will be fused into a solid bone plate.

* Biscopea - Implanted into the chest cavity, this implant massively bolsters muscle development and fiber density throughout the Marine's body by unleashing a wave of hormones. This is commonly implanted at the same time as the Ossmodula.

* Haemastamen - Implanted into a main blood vessel like the aorta, femoral artery or vena cava, the Haemastamen alters the Marine's blood composition to carry oxygen and nutrients more efficiently.

* Larraman's Organ - This organ manufactures Larraman Cells. These serve the same purpose as the baseline human body's platelets, but act faster and more effectively. When a Space Marine is wounded, Larraman Cells are released, attached to his leukocytes. At the site of the injury, they form scar tissue in a matter of seconds, effectively preventing massive blood loss and infection.

* Catalepsean Node - Implanted into the back of the brain, this implant allows a Marine to avoid sleep, instead entering an almost comatose trance where they "recharge". It also allows the resting of half the brain while the other remains alert, thus removing the need for total sleep. The longest known record of any Space Marine going without rest while on active combat duty is 319 hours by a member of the Dark Angels.

* Preomnor - The Preomnor is a decontamination chamber inside the chest cavity. It is capable of chemically analyzing ingested materials and neutralizing most known toxins. The Preomnor enables the Marine to eat normally inedible substances and resist poisons.

* Omophagea - Implanted into the upper spinal cord, this organ is designed to absorb information and DNA related to experience or memory. This enables the Marine to gain information, in a survival or tactical sense, simply by eating an animal indigenous to an alien world.

* Multi-lung - The multi-lung is a third lung, able to absorb oxygen from environments usually too poor in oxygen to allow normal human functioning. Breathing is accomplished through a sphincter in the trachea, allowing all three lungs to be used at full capacity. In toxic environments, a similar muscle closes off the normal lungs, thus oxygen is absorbed exclusively by the multi-lung which filters out poisonous elements.

* Occulobe - Essentially, this organ enhances a Marine's eyesight, granting him exceptional vision and the ability to see normally in a low-light environment.

* Lyman's Ear - This implant renders a Marine immune to dizziness and nausea(seeCochlea), and enables a Marine to consciously filter out "white noise".

* Sus-an Membrane - This implant allows a Marine to enter a catatonic or "suspended animation" state. It can allow a mortally wounded Space Marine to survive his injuries, and bring the metabolism to a standstill. The longest recorded period of this state was with Brother Silas Err of the Dark Angels for 567 years.

* Melanochrome - Linked to pigment cells in the skin, this allows the Marine's skin to shield him from otherwise dangerous levels of radiation and heat.

* Oolitic Kidney - This organ works in conjunction with the Preomnor, filtering the blood to remove toxins.

* Neuroglottis - This organ implanted in the mouth allows a Marine to assess a wide variety of things simply by taste. From poisons to chemicals to animals, a Marine can even track his quarry by taste alone.

* Mucranoid - Altering the Marine's sweat glands, this organ causes the secretion of an oily substance that coats the skin when necessary, protecting it from extreme temperatures and to some extent, even vacuum environments.

* Betcher's Gland - Implanted into multiple locations inside a Marine's mouth, these glands transform a Marine's saliva into corrosive, blinding acid when triggered. A Marine trapped behind iron bars would be able to chew his way out given a few hours.

* Progenoid Glands - Implanted into both the neck and chest cavity, these glands serve to collect and cultivate the gene-seed from a Space Marine's body, and to safeguard it for the continuity of a Chapter. The neck gland is removed upon 5 years, and the chest gland upon 10 years; both are then used to create new organs for new Space Marines.

* The Black Carapace - The last and possibly most important of all implants, this neuroreactive material is implanted directly under the skin in the chest area. Invasive fibre bundles then grow inward and interlink with the Marine's own nervous system. Points pre-cut into the Carapace are effectively connection points, allowing a Marine to directly interface with his suit of Power Armour.