Changes

A Marine's gene-seed may be rendered useless by exposure to high levels of radiation. Also, over time a Chapter's gene-seed may change through genetic mutations, so that specific implants become corrupted, producing new effects in Marines, or becoming useless altogether. A corruption in the Chapter's genetic material can lead to the Chapter's extinction. This is why gene-seed must be constantly monitored for mutations. {{Cite This}} Each Chapter chapter is obliged to send tithe 5% of its genetic material gene-seed to the [[Adeptus Mechanicus]] on [[Mars]]. The first purpose for this is that it enables the Adeptus Mechanicus to monitor the health of each Marine Chapter. Secondly, The second is that it enables creates a store of preserved gene-seed to be used for funding new Chapters.{{Fn|15}} The creation of the Adeptus Mechanicus gene-seed to be used for founding a new Chapter is a lengthy process. A single suitable gene-seed is selected and used to store create a zygote. Zygotes are then grown in culture and implanted into test-slaves, which must be biologically compatible and free from mutation. Test-slaves are little more than physical mediums for the creation of gene-seed , and as such are bound in experimental capsules, where they remain conscious but are completely immobile. The process begins with a view to founding new Chapterssingle implanted slave, whose body produces two progenoids. These are implanted within two more slaves, that then produce four progenoids; this process is repeated until 1,000 healthy sets of organs are produced, which takes about 55 years of constant reproduction.{{Cite ThisFn|15}} Per Imperial law, only the Emperor is authorized to decree the founding of a new chapter. In practice, this is done by the [[High Lords of Terra]] speaking in his name.

Reproduction of gene-seed is possible through the Progenoid glands - , implants whose sole purpose is the replication of gene-seed. A mature gland can be removed by an [[Apothecary]] and new organs artificially cultured from it. This is the only source for new implants, so a Chapter depends on its Marines to create other Marines. In the battle-mysticism of the Astartes, the gene-seed is regarded spiritually - though although a fallen Marine's body is dead, he lives on as gene-seed that returns to the Chapter.{{Cite This}}