Making DNAM's in (1st ed) Mongoose 2300AD follow Mongoose Traveller Rules

Bryn the 2300AD guy

Banded Mongoose

Making DNAM's in Mongoose 2300AD follow Mongoose Traveller Rules

Mongoose 2300AD (the 2012 version at least) is simply a reskin of QLI's 2320AD. I noticed when looking at the DNAM (DNA Modification) rules, trying to calculate the chance of dying if infected with the DNAM virus (about 1 in 6 in the original GDW rules) that very little had changed from 2320AD. Indeed, for the most part only the only change was from D20 difficulty class to a Traveller difficulty class. However, Mongoose Traveller rules are more subtle than D20, and the effects are graduated.
A search through the rules has shown only one task properly formatted for Mongoose Traveller; exceeding the 7.7 ly limit. This was an addition, which was not present in the 2320AD text. This is general - tasks that were present in 2320AD were not properly reformatted to the Mongoose Traveller rules, with only the DC changed, and the graduated success system ignored.

There was one other change, which was a clarification of the 2320AD rule, which was ambiguous. However, the Mongoose Traveller resolution goes in the wrong direction from a scientific standpoint. I'll address that at the end.

This will properly adapt the DNAM rules in 1st edition Mongoose 2300AD to Mongoose Traveller rules. If the 2nd edition fixed this, I'd love to know. I own every product from the 1st Mongoose edition that got a physical release, but only the AEH from 2nd edition. The AEH was so poorly done that it put me off buying anything else at those prices.

The Task Systems
We have three task systems in play; (GDW) 2300AD, T20 and 1st ed. Mongoose Traveller. 2300AD and Mongoose are both derived from the Megatraveller task system with refinements and modifications.

2300AD (2nd GDW ed.) used a d10, with a base target number of 6+ for routine tasks, and difficulty levels moving in bands of 4 (10+ for difficult, 2+ for simple etc.). Several different bonuses could be used. The time taken was 3d6* the listed time. Failure meant rolling on a failure table that could allow a go-around, prevent another attempt, or do serious damage for a fumble, upto straight death in the case of the DNAM transformation. The bonuses were characteristics (0 to 5, with the norm being 2 or 3) and skills. Traveller:2300 had a general target number of 7+ for routine, but rolled effectively on a d10-1 (i,e. 0 was read as 0, not 10), for a lower chance of success, but with the same consequences.

Mongoose uses an elegant modification of Megatraveller, wherein the roll is 2d6 and the base target 8+. Modifiers are applied to the roll, including difficulty in steps of 2 (-2 for difficult, which equates to a 10+ target etc.) and bonuses on the same scale as 2300AD. The interesting wrinkle is that the degree of success of failure is determined simultaneously by how well you beat (or failed) the dice roll, thus:
  • Beat the target by 6 or more = exceptional success. It worked brilliantly, having better than expected effects.
  • Beat the target by 1-5 = success. It worked.
  • Beat it by 0 (i.e. rolled the target) = marginal success. It sort of worked, but with caveats.
  • Failed the target by 1 = marginal failure. Almost succeeded.
  • Failed the target by 2-5 = failure. It didn't work.
  • Failed the target by 6+ = exceptional failure. You make things much worse.
Bonuses are characteristics (-2 to +2, with -3 and +3 being just possible but vanishingly rare and 0 being the norm) and skills.

The D20 (i.e. 3rd edition of Dungeons and Dragons) system used by T20/2320AD rolled a d20 against a difficulty (10 for average tasks, 15 for tough tasks etc.). Success/failure is digital, with no gradations and no possibility of a fumble. Characteristic modifiers go from -4 to +4, with 0 being the norm (a characteristic of 10-11 is a zero, 12-13 is +1, 14-15 +2 etc. in both directions).

What Is a DNAM?
As described in the GDW core canon, the virus is a "controlled cancer." It mutates cells and has them proliferate rapidly. The new tissue displaces the old tissue. It changed between editions. In the 1st GDW edition it was described as an emerging experimental procedure, but the author of the King section of the Colonial Atlas relocated the first use back to 2192, and so the experimental line was deleted in the 2nd edition in a retcon. As described in the CA:
At first, the extreme gravity of the planet made any form of extensive colonization unthinkable. Despite these problems, the lure of King's natural resources demanded that the scientific community find some way to overcome this problem. After numerous attempts
at mechanical compensation had proven impractical, a team of researchers working in conjunction with the Canadian government found a solution. In 2192, they created a new form of life, known as DNA Modifiers (or DNAMs), that was to open King up to
Similar in structure to Terran viruses, DNAMs enter the cells of the host's body and make changes in the structure of their DNA. When the altered cells reproduce, the offspring are unlike their parents in some way. One of the changes induced by all forms of DNAM is the rate of reproduction. The modified cells multiply much faster than their normal counterparts in a manner that has been likened to a controlled cancer. Once all of the cells are changed, the rapid growth slows to normal, and the intruding microbes die off. In most cases, it takes just over a month for the DNAMs to do their work in a human body. During this time, the host is normally kept sedated in a medical facility.
The task profile to undergo DNAM transformation is as follows: To undergo DNAM transform: Simple. - Physical Endurance. 3 days.

DNAM transformation is a hazardous task. If the task results in failure, a roll of "retry" means the DNAM was rejected by the body and "check determination" indicates the DNAM was rejected with unpleasant side effects. If a mishap is incurred, "superficial
damage" results in serious, permanent medical complications as a side effect of the DNAM rejection. Any result more serious than this level indicates death. It should be noted that Physical Endurance acts as a negative modifier since a stronger immune system will act to resist and complicate the transformation process.

If the task is successful, the character's body type is converted to "mesomorph" (this change is in game terms and not so much in appearance). To reflect this, the original physical attribute modifiers should be neutralized and the mesomorph modifiers applied. Beyond that, DNAM modified characters receive +(1D6-3) to Strength and Physical Endurance and -(1D6-4) to Dexterity. In each case, the minimum modifier result is 1. This task process should be performed during character generation (at the end of step three in the character generation checklist) if a player wishes to run a King colonist as a PC.
As a task, it is roll 3+ on a d10 to succeed, but with the endurance characteristic (on average 2.5) as a penalty, leading to a 45% chance of success on average. It takes, on average, about 30 days (3d6*3 days). As a hazardous task, the effects of failure can be extreme, and there is a 50% chance of a mishap or serious mishap. If you get a mishap, you have a 50% chance of dying, and a serious mishap is 91% dead. This averages as a 60% chance of death if you have a (serious) mishap. The chances of dying outright are thus 55% * 50% * 60% = 16.5% or 1 in 6. (See here)

If played with 1st edition Traveller:2300, reformatted to a normal d10 the target number would be 5+, and so success would occur 25% of the time, and death would be proportionally more common.

I would argue from the biological standpoint that if you fail the roll, you have antibodies against the DNAM and can never attempt it again, but that's not stated. If you allowed the players to keep going round it would ultimately resolve as 73% transformed, 37% dead.

Mongoose Task: Being Transformed by the DNAM Virus
The 2320/Mongoose rules define major or minor DNAM's, with the difference being a major DNAM is no longer Human, and cannot breed outside of their race. Minor modifications are done on an outpatient basis, and take a month to complete, whilst major modifications require three months as an inpatient, generally sedated.

For Mongoose, the Fortitude check was simply changed to an endurance check. However, the degrees of success/failure were not changed. The digital D20 system was kept in place. Adding the degrees of success/failure to the task would be:
  • Exceptional success: basically impossible, but perhaps remove (some of) the negative effects of the DNAM from the character.
  • Success: the character is transformed with no long-term effects.
  • Marginal success: the character is transformed, and must save against long-term permanent medical complications with a +2 bonus.
  • Marginal failure: the character is transformed, and must save against long-term permanent medical complications.
  • Failure: the character is not transformed, and must save against long-term permanent medical complications.
  • Exceptional failure: character is dead (or reduce endurance by 2d6+1 and make them crippled).
For the save vs permanent damage, make a routine (8+) endurance check for a minor DNAM or difficult (10+) for a major DNAM. On a exceptional success there is no damage. On a success the character permanently loses 1 endurance, or 1 plus special effects on a marginal success. On a marginal failure the character loses 1d6 endurance without additional effects, and 1d6 with additional effects on a failure. On an exceptional failure the character loses 2d6+1 endurance and crippled/ killed.
In the event of permanent medical complications, in addition to reduced endurance, other effects related to the specific tissues the DNAM virus targeted will occur. With a thinair modification, the lungs are seriously damaged, causing the requirement to use a respirator for example. With a King DNAM they get brittle bones and damaged heart tissue etc.

Whether repeating the DNAM treatment on a failure is possible is an interesting issue. In 2320AD the rules was that a second treatment made the character extremely ill if success, and was often lethal if failed (on the second try). A third try was impossible. In Mongoose, this was changed, I think by a simple misreading, and you had two tries with a third being impossible, but also rules for damage if the third try failed. There was also penalties for having multiple DNAMs (-2 on the rejection save per minor and -4 per major).

Given the ambiguity in the status of the third attempt, the best solution is to have cumulative penalties per DNAM attempt, whether successful or not.
Thus, for multiple attempts, each attempt at a major modification, successful or not, inflicted a -4 penalty on all future DNAM attempts, whether the same virus or a different one (since the carriers will be similar). For each minor attempt, a -2 penalty is accumulated.

Assuming a difficult DNAM (i.e. King) as the norm, probabilities are:

For a normal colonist taking the King DNAM, they have a 1 in 6 chance of dying in the attempt, and a 28% of being transformed (with or without complications). This is the same chance of death as the GDW King DNAM, but a slightly lower chance of success using 2nd edition, or a higher one than 1st edition. All in all, the numbers are roughly consistent with the GDW canonical numbers.

A normal colonist taking a simple DNAM (8+) is the same as on the +2 column, and is transformed nearly 60% of the time, and the death rate is around 3%.


These rules utilise the improvements in the task system of Mongoose Traveller over D20 2320AD. They give a graduated range of possibilities, and have a strong possibility of dying or doing serious damage to a character. They preserve the danger of DNAM in GDW 2300AD, which was largely done away with in 2320AD, and hence give a result closer to the prime canon.

Further, the strong possibility of a serious mishap acts to balance the DNAM and explain the low rate of DNAMing. Most people simply wouldn't deliberately give themselves a form of (hopefully controlled) cancer in order to get a stat bonus.
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Very useful, thank you for posting this.

I wonder what the provolutionists do with this technology :)

And what happens when a pentapod bullet returns knowledge of this to its maker.