Talk:Genetics

My Sim has black hair and her future husband has red hair. But my Sim's dad has blonde hair, and her future husband's dad does, too. Does that mean they could have a blonde baby? Sparrowsong 04:44, March 20, 2010 (UTC)

I think it could be possible. —Preceding unsigned comment added by DavidMC123 (talk • contribs) - Sign your comments with ~

Yeah, actually, it's even likelier that their children will have blonde hair rather than red. If your sim's dad is a pure blonde (that is, he has two blonde alleles), then your sim has one black allele and one blonde allele. Similarly, your sim's future husband has one red allele and one blonde allele if his dad was a pure blonde. So, there's a 50% chance that their children will have black hair (because black is dominant and will always be shown rather than the recessive allele). In 25% of the cases the child will be pure blonde and in the remaining cases the game will decide randomly if they're blonde or red-haired (because both red and blonde are recessive traits). All in all, there is a 37,5% chance that they'll have blonde children. Granted, all of this is assuming the grand-daddies were pure blondes. If they weren't, then it's a lot more complicated to foresee. Crusoe704 22:46, March 27, 2010 (UTC)

Skin Colors
The section on Skin Colors says:

"Skin colors work differently. The 4 skin tones are S1 (white), S2 (tanned), S3 (brown) and S4 (dark brown). They work on the same pattern of allele transmission, but the way the alleles are expressed depends on both. A person will have a skin tone chosen randomly between the tones of his alleles. A S2/S4 alleles person will have a skin ton of S2, S3 or S4, chosen randomly. S1, S2, S3 and S4 are equally recessive. Only alien skin tone seems to be dominant. Hence, a person with A/S1 will be green, always."

This implies something that I have not been able to verify in several "experiments", namely for example that a sim with S1/S4 alleles and an S4 skin tone could pass on anything other than S4 to her child. I tried this several times and it just doesn't happen. Two S4 people will always have S4 children, no matter what their genetic make-up is. My theory is that where the normal skin colors are concerned, the game does not store the alleles used to determine the sim's skin color, it only stores what color the sim is. So for example an S2 sim will always pass on the S2 skin allele to her children even if her parents were S1 and S3.

Alien skin (and maybe custom skin?) is treated like in the above quote however.

If there are no objections to this, I'll edit it in a couple days accordingly. Crusoe704 23:11, March 27, 2010 (UTC)

Strange Genetics
In my game, my sim Anna has black hair and green eyes and so do her parents. She married Parker Lawson who had brown hair and greyish eyes. His father had black hair and greyish eyes his mother had reddish hair and brown eyes. Anna and Parker had a child called Klaudia she had Bright blond hair and blue eyes unlike anyone in her family. Where did these genes come from. Anna didnt mess around with any other guy. And they had another child a boy called Alexander with Brown hair and green eyes. This is annoying me and she doesnt look like anyone in her family. Where did these genes come from???
 * Genetics is a bit weird, even in real life. There could be some hidden genetics in your sim, or maybe the game is just messing with you. If you have SimPE, try using that to look into their DNA. --W H  (Talk) 07:51, May 27, 2011 (UTC)

First born effect
Are there any hacks that automatically shake up the randomizer so i dont have to remember to do it myself? I always forget and end up with identical kids. It isnt normally a problem because most of my families only have one kid (its a large neighbourhood, sometimes I have trouble keeping track otherwise) but occasionally they have two and I dont realise I've forgotten until the kids grow up looking identical. Sims2addict9312 (talk) 08:53, September 10, 2012 (UTC)


 * Not that I'm aware of. The "batbox" has an option for that, but it has to be used manually, and I don't know how well it works. Dharden (talk) 12:12, September 10, 2012 (UTC)
 * Also, using the batbox randomizer will switch your game to neighborhood view, so don't forget to save before using the option.  Nikel  Talk  –  Vote!  08:56, September 11, 2012 (UTC)

Identical Twins
Can the game generate identical twins or do you have to make them yourself? (sims2) Sims2addict9312 (talk) 08:53, September 10, 2012 (UTC)


 * You can make them in CAS, but twins born in-game are always fraternal. You'd probably have to use SimPE to modify one twin. Dharden (talk) 12:12, September 10, 2012 (UTC)

I've had twins that were almost but not quite identical before. --  C.Syde  ( talk &#124;  contribs ) 03:47, June 24, 2014 (UTC)

Pointed ears
I am playing with a family of fairies. It consists of the mother, Yaroslava Tkachenko, the father, Branch Tkachenko and their sons Artem and Taras Tkachenko, and daughter, Oksana. The funny thing is that Artem who is toddler has pointed ears. There's nobody else in the family who has it. The question is how do he get that. Надія(hope),сла́ва (glory), Любов (love) ( talk here ) 16:51, October 6, 2012 (UTC) Lesya Zirka

Forget it I was wrong. Надія(hope),сла́ва (glory), Любов (love) ( talk here ) 21:48, October 6, 2012 (UTC) Lesya Zirka
 * Is it The Sims 2 or 3? If it's The Sims 2, you may also want to read this.  Nikel  Talk  –  Vote!  05:29, October 8, 2012 (UTC)

Concerning dominant traits

 * Two (dark) blue-eyed parents can have a brown-eyed child if one of the child's grandparents have brown eyes. Melody Tinker is an example of this. In real life, this is extremely rare. An individual carrying a brown-eye allele and a blue-eye allele is meant to express brown eyes (being the dominant trait); however if the blue-eye trait is expressed over the brown-eye trait then the individual may be mistaken as homozygous for blue-eyes (two blue-eye alleles), thus the individual's offspring is expected to have blue eyes too.
 * Can anyone confirm this as being true? Ѧüя◎ґ (talk) 21:43, June 14, 2014 (UTC)

Don't think that's true. At least one of the parents has to have brown eyes or genetics for brown eyes to produce a child with brown eyes. Melody Tinker's eyes are different from the rest of her family because she was made in Create a Sim and / or Body Shop. Until further evidence turns up, I doubt that it's true.

It's also the same with Albany Capp and Richard and Anne Norman. Also when using the Tombstone of Life and Death or SimPE, one can see that Albany was actually created before his parents, meaning that he wasn't born in-game.  C.Syde  ( talk &#124;  contribs ) 02:58, June 15, 2014 (UTC)

Genetics
According to how SimPE / The Sims 2 works, there can only be one dominant genetic and one recessive. Looking at SimPE, it seems that if there are four different genetics available to inherit, one will be dominant, one will be recessive and the last two will be dropped completely.

Any ideas / agreements? --  C.Syde  ( talk &#124;  contribs ) 06:12, June 24, 2014 (UTC)
 * Each parent gives off one allele to their offspring. I assume that's what you mean when you say "the last two will be dropped completely". Ѧüя◎ґ (talk) 06:26, June 24, 2014 (UTC)

Yes. --  C.Syde  ( talk &#124;  contribs ) 06:27, June 24, 2014 (UTC)


 * For eye and hair color, what SimPE shows as "dominant" and "recessive" might be better thought of as "expressed" and "non-expressed". Each parent gives one allele, but it's possible for both to be dominant or recessive, in which case the game will randomly pick one to be expressed. Dharden (talk) 22:51, June 24, 2014 (UTC)


 * Skin tone is ... different. As far as I can tell, if alien-skin genetics are not involved, "Skintone" is the same on each side, and is the Sim's actual, expressed skin tone, while the "Skintone range" values are what got passed from the Sim's parents. So, a Sim might have "Skintone" values of 00000002-0000-0000-0000-000000000000, but "Skintone range" values of 00000001-0000-0000-0000-000000000000 and 00000003-0000-0000-0000-000000000000 . I'm not sure which one gets passed on, but since the Strangetown pre-mades that are missing "Skintone" have "Skintone range", I think it may be "Skintone range". If alien-skin genetics are involved, it appears that the "Dominant" side shows the Sim's expressed skin tone, while the "Recessive" side shows skin genetics received from the other parent. In these cases, the "Skintone" and "Skintone range" values on each side are the same. Dharden (talk) 23:40, June 24, 2014 (UTC)


 * If I am reading what the Prima guide for TS2 says about skin tone genetics right, and if Prima got it right way back then, if a Sim gets a gene for a skin tone that is outside the normal 00000001-0000-0000-0000-000000000000 to 00000004-0000-0000-0000-000000000000 range, skin tone selection becomes a straight 50/50 choice between the two skin tone genes that were passed on. I don't use custom skin tones or the mannequin tone, but this squares with what I have seen when looking at the Sim DNA of Sims with alien-skin genes. Dharden (talk) 15:18, June 25, 2014 (UTC)

For example?
For example, a child may have his/her mother's eye shape, but the father's eye size

Sure about that one? In all the times my Sims have had children, they've had either their mother's eyes or their father's eyes. Never their mother's eye shape but their father's eye size. Until further evidence turns up I doubt whether this fact is true. --  C.Syde  ( talk &#124;  contribs ) 08:39, June 24, 2014 (UTC)


 * I'm trying to recall why I concluded that eye shape and size are inherited separately. Dharden (talk) 22:32, June 24, 2014 (UTC)

I've removed that information, due to the lack of evidence suggesting that it is true. My past experience in-game also contradicts this. --  C.Syde  ( talk &#124;  contribs ) 04:02, June 26, 2014 (UTC)

Alien skintone always dominant? (TS2)
IME, this is not the case. At least, it is not the case when one of a child's parents is an alien-Sim hybrid with the alien skintone, and the other has a skintone other than the lightest. In those cases, even if the alien skin tone is passed on, the child may have a normal skin tone, and the alien skin tone may be recessive. I know this because I have observed it; one of the Sims in my current 'hood is dominant for brown eyes and medium skin, but carries alien eyes and alien skin as recessives. Dharden (talk) 13:35, June 24, 2014 (UTC)

I'll take your word for it, but I've never seen that happen. I've had brown eyes and brown hair as dominant alleles over alien genetics, and I've had mannequin skin tone as dominant over alien genetics. But I've never had a normal skin tone be dominant over alien / mannequin skin before. --  C.Syde  ( talk &#124;  contribs ) 19:07, June 24, 2014 (UTC)


 * I haven't seen it often, but I have seen it. IME, it only seems to happen if the hybrid parent is heterozygous for the alien skin tone. In that case, a passed-on gene for alien skin does not appear to be treated as dominant, and the resulting child can have both a normal skin tone and a non-expressed gene for the alien skin tone that can presumably be passed on. (I'll have to wait until they reach adulthood to find out for sure. but I see no reason to think that it could not happen.) Dharden (talk) 22:29, June 24, 2014 (UTC)

Grey hair
I know 00000005-0000-0000-0000-000000000000 is the code for grey hair, but I always thought that grey hair was *not* genetic. Dharden (talk) 02:35, July 10, 2014 (UTC)