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As a student of genetics, I notice this incorrect usage of terminology... all the time in ha-rpg. And to be honest, it drives me a little batty, so I figured, why not post a journal to point out correct terminology and basically stop ranting in my head? :P

Definitions:

Gene: A DNA sequence that codes for a protein.
Allele: Two or more variations of a gene.
Dominant: A gene that only needs one allele to be expressed
Recessive: A gene that needs two/all alleles to be expressed
Heterozygous: All/some alleles are different
Homozygous: All alleles are the same/similar

Alleles are part of genes, but genes are not part of alleles. Using 'gene' to describe an allele is easy to mistake, but it is wrong.
A gene is a whole, alleles are part of the whole and what make up the coding of the gene an organism has. Each gene has two alleles, that may or may not be the same, depending on inheritance. They make up how the gene is expressed in the individual and may or may not surpress the expression of other genes. Confused yet?

Let me first point out that Dominant and Recessive do NOT refer to Alleles. They refer to the expression of the gene itself. It is easy to get confused, as some journals and documents use dominant and recessive  in conjunction with heterozygous and homozygous to explain both the expression of the gene and the number of same alleles(In horses, diploid, or two.) 

A dominant gene would be silver. Why? Because you only need one copy of silver to be expressed on the horse. HOWEVER, a horse with only one copy of silver is NOT referred to as recessive. Why? Because whether or not they have a silver offspring, they still have the chance of producing a silver without needing another copy of silver from the other parent. A horse with one copy of silver is referred to as heterozygous for silver.

A recessive gene is flaxen. Why? You need two copies of the flaxen gene to have flaxen expression. Therefore, any horse that has flaxen expression would be considered homozygous for flaxen. NOT recessive, NOT dominant. It carries a recessive gene, but it has both copies of it. Makes sense? Any foal it has will NOT express flaxen, unless a flaxen is given from the other parent.

However, that foal can foal a flaxen, if bred to another flaxen carrier. Both of these carriers would be considered Heterozygous, because they have one flaxen allele, and one non flaxen allele.


Ex:
Genotype: Ee/aa/Lplp/Toto - Black pintaloosa
Allele: E and e -Heterozygous
aa -homozygous
Lp and lp - heterozygous
To and to - heterozygous

Overall, this horse is heterozygous for everything. (aa is not counted because it does not affect anything.) It is not dominant or recessive for anything as all these genes are co-dominant.

Genotype: ee/AA/ff - Flaxen Chestnut
Allele: ee- homozygous
AA - Homozygous
ff- homozygous

This horse is homozygous for everything. This is where it gets tricky. ff is the recessive gene that needs two copies to work, so many people will call it homozygous recessive. This is still not referring to the allele, f, but to the whole, ff. It is recessive because if a F is thrown in there, it changes the expression.

BUT, you can't just drop the homozygous and call this horse a recessive. Because it is not. Each allele it has, because it's homozygous, it will give to the next offspring and some phenotype will be shown. The only thing truely recessive about this horse is that it carries the recessive gene, flaxen. Therefore, this horse is homozygous for all genes and expressing the recessive gene, flaxen.

Toto -not recessive, heterozygous
Znzn - not recessive, heterzygous
EE - not dominant, homozygous
LPLP - not dominant, homozygous.

Most horse colour genes are NOT dominant, because they coexist with other genes and modify the expressions. At most, they will be referred to as epistatic dominant genes, which basically means that it has varied expressions that cannot really be predicted, such as overo and tobiano and only need one allele to be expressed.

Makes sense?

Therefore, your DOM mutation nordies... are not DOM at all. They are Homozygous.

Want more information on how genes and alleles work? Check this in depth explanation out.harpg-newsletter.deviantart.co…





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:iconbovidaeloony:
bovidaeloony Featured By Owner Jun 16, 2014
I work in a bio lab and the misuse of these terms drives me INSANE. 
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 16, 2014  Hobbyist General Artist
I can just imagine.o0 It was driving me a bit crazy and I'm just a student. I can't imagine how professional biologists/scientists feel when people misuse terms to describe things and don't realise that they aren't describing what they think they mean.

Hopefully though, this will help, even a little. At least the information is out there.^^
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:iconmaiise:
maiise Featured By Owner Jun 16, 2014  Hobbyist
Thankyou so much for this! I'm also studying DNA/Genetics at school and it frustrates me to see a lot of misconceptions around genes and "dominant" and "recessive" genes. :clap:
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 16, 2014  Hobbyist General Artist
You're welcome! It was one of those, 'if I don't do it, it'll drive me crazy' things. xD

Yay genetics study~ :D

There's a lot of misconceptions around genetics in the population today, especially when you start browsing sites that host 'genetic' information, or stables who decide to inform people about horse colour... and don't understand it fully themselves.
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:iconmaiise:
maiise Featured By Owner Jun 17, 2014  Hobbyist
Totally understand that!
Yeah! Its super interesting and I'm really enjoying it so far c: I've found with the created breeds theres a lot of misconceptions of genetics there, and its pretty frustrating.
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 17, 2014  Hobbyist General Artist
Me too.^^ It's something I never get tired of learning about.

Yeah, my biggest one is this one here, and rating shades of a colour as 'rarer' than another. You can't control shades in breeding, that's something caused by environment and random factors(as far as I know). You have an equal chance of getting a blood red chestnut and a dull chestnut.
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:iconmaiise:
maiise Featured By Owner Jun 17, 2014  Hobbyist
Exactly! People seem to forget that the environment surrounding the horse can have an impact on their phenotype (I learnt about this just the other day haha!) And its kind of frustrating to see it repeatedly done wrong over and over again.
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 17, 2014  Hobbyist General Artist
Even geneticists seems to, from what I've learned. The whole, is it environmental or genetic? From what I've learned and read, it's really both. xD You can't rule out one and focus on the other. Diet, environment, what the dam ate when she was pregnant, what they got from both parents, all plays a role, small and large.

It is, but I guess people decide to take creative license in some things. Which I'm totally fine with, if they state it. I'm still not big on having natural colour shades 'rarer' than others, but I'm okay with taking certain genes and having them expressed on coats they naturally wouldn't be expressed on if it's a mythical dA breed. (Like cavitto, who can have silver and flaxen on all bases. But the horses themselves were the 'gods' horses and thus don't really follow general horse rules anyway, and it's stated right in the journals that this is the case. :P)
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:iconivy020:
ivy020 Featured By Owner Jun 16, 2014  Hobbyist Digital Artist
Thank you! This will help out with my life  a lot.
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 16, 2014  Hobbyist General Artist
You're welcome!
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:iconivy020:
ivy020 Featured By Owner Jun 18, 2014  Hobbyist Digital Artist
:D
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:iconnebunezzari:
Nebunezzari Featured By Owner Jun 16, 2014  Hobbyist Digital Artist
Being a horse genetics hobby nut, I knew the difference between dominant and homozygous, ashamed to say that seeing 'dom' everywhere to describe homozygous mutations implanted itself on my brain and I forgot how wrong it was. Thanks for the reminder! xDD
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 16, 2014  Hobbyist General Artist
xDD I think that's why it bothers me so much. I started using it in my head, and then I'd start confusing myself when doing schoolwork. So basically, this is me telling everyone to stop messing with my brain. xD

You're very welcome!
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:iconnebunezzari:
Nebunezzari Featured By Owner Jun 16, 2014  Hobbyist Digital Artist
:shakefish: yes stop messing with our brains! Oh dear I think I would have started getting confused too if I had homework involving genes too :P
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 17, 2014  Hobbyist General Artist
Lol yeah, it was pretty interesting to proofread, I must say. xD
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:iconnebunezzari:
Nebunezzari Featured By Owner Jun 17, 2014  Hobbyist Digital Artist
Lol I bet :P
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:iconnixxily:
Nixxily Featured By Owner Jun 16, 2014  Hobbyist General Artist
Thank you!
Glad somebody is pointing this out.


What's your field of study in the genetics? :) All animals, or specific something? :)
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 16, 2014  Hobbyist General Artist
xD And I'm glad I'm not the only one it's been bothering.

My field of study right now is in animal genetics and breeding.(mainly livestock.) I'm still trying to decide where to narrow the field down to go into something specific. I'm actually wavering between pursuing horse genetics for my masters or going on to finish my degree in forensic anthropology and do something with genetics in the forensic field. Too many choices.
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:iconnixxily:
Nixxily Featured By Owner Jun 16, 2014  Hobbyist General Artist
I've never studied genetics more intensely, but in my country you start learning the basics at the age off 12. And it gets repeated and deeper ever 2 years. The basics always stuck around for me. I loved it ^^

nice! 
Mainly livestock? So horses, cows, chickens ... those animals? Is it just me, or do all genetics in mammals sorta have some equal genetics? :)
I like how birds turn the gender ... something around (what's the word again?) not XX and XY, but O and Y or something?
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:iconathenamyth:
AthenaMyth Featured By Owner Edited Jun 16, 2014  Hobbyist General Artist
Here we don't touch on the 'genetic' part until around grade 11, 12, so age 15, 16. We start with cell biology at age 12 and it just gets repeated and a bit deeper from then on, even into university. Cell division and meiosis and mitosis. *hits head* To me, that's the boring part of genetics. The fun parts are inheritance and population factors, things that cause people and animals to have the genetics they have.

Those animals, yup.

They do. All animals are diploids(two alleles) and many can have similar types of alleles that can do similar things in each species, but are slightly different. That's why they research mice for certain genetic diseases and pigment mutations in humans and other creatures, because its a good bet that the gene is located in a similar spot on a chromosome.

Gender determination? I believe it's Z and W. It's used for fish and some reptiles too. xD ZW is female, and ZZ is male.

My favourite one is the temperature dependant genders. xD Be born at the right temperature range, you can be a boy. Another temperature range, you're a girl. Can you imagine?
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:iconnixxily:
Nixxily Featured By Owner Jun 16, 2014  Hobbyist General Artist
True! I wish I was still in collage ...

sweet! Mice are some of the perfect species for that, given how quickly they breed and grow up ^^
I'm trying to figure out all colors in mice, I really like to learn more. Same as in dogs and cats.

Yup that one! Thank you ^^ it's been a while since I actually had a course on them ^^

:giggle: I saw that on discovery and just try not to go "teenage mutant ninja turtles!" 
You sure know at what temperature they were hatched xD

The thing that surprises me, is how little the temperature difference has to be! it's soo little! But it is handy, like in zoo's for breeding programs! with mammels, you're just unlucky if you get the wrong gender, with reptiles, (and I think some others too right?) it's just, we need males, set the temperature at that! :o
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 18, 2014  Hobbyist General Artist
I'm currently 'teaching' myself dog genetics and I must say, its not as straight forward as horse, which I was surprised at. I figured horse genetics would be more complex. I haven't looked at mice yet, but I can imagine they'd be pretty interesting as well!

It's very handy in situations like that, you're right. xD Good way to make sure you have the pairs you need to continue their species, unlike mammals, where you hope for the best. (Yeah, it happens in some fish too I guess.) It's probably a good way to tell how temperatures were that year are as well, as long as you can find the date of gestation and hatching. xD Let's make that complicated...
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:iconnixxily:
Nixxily Featured By Owner Jun 19, 2014  Hobbyist General Artist
They are and they're so complex! I sorta want to do a tutorial on them once I get a little bit of a grip, because I have a mouse breed :XD:
This thing is sooo awesome if you ever want to get into mouse genetics - www.fancymicebreeders.com/phpB…
And these are great for images: www.thefunmouse.com/varieties/…  -  everwildrattery.webs.com/genet…

Yea, dog genetics are surprisingly hard! I keep trying but I should only do 1 animal at a time :XD: that will make them simpler! 
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 21, 2014  Hobbyist General Artist
*tucks links away for the future*

Oh, that will be cool!

Haha they really are. Threw me for a loop with liver being a black based gene the first time I looked at it. Totally different than horses. XD

Lol One animal at a time would probably make it much, much simpler. :D
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:iconoakhollowd:
oakhollowd Featured By Owner Jun 16, 2014  Hobbyist Digital Artist
:la: thank you for being fussed enough about this to put it into (easy to understand) words! Always wanted to but was far too lazy. Very well written!
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 16, 2014  Hobbyist General Artist
Thank you very much for your comment!

It's been dwelling on my mind for awhile and honestly (in my mind anyway), is a very important distinction if you're going to do any kind of science involving inheritance, genetics or biology. ^^
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:iconoakhollowd:
oakhollowd Featured By Owner Jun 16, 2014  Hobbyist Digital Artist
No problem :)

Oh definitely! I think a lot of HARPG players have at least a mild interest in those areas too, so this kind of knowledge is good. Plus it doesn't get much harder in your first year of university!
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 16, 2014  Hobbyist General Artist
Exactly! Those definitions at the top are a regurgitation of my first university genetics class. xD We got drilled on those all semester, so it's stuck with me ever since.
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:iconevello:
Evello Featured By Owner Jun 16, 2014  Student General Artist
Ahhh the genetics. <3
I've only ever had a high school level of teaching this but I've always found it SO cool xD
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 16, 2014  Hobbyist General Artist
Me too... It's one of the reasons why I changed what I was doing a degree in halfway through... XD I love it though, even if the cell parts are boring.
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:iconevello:
Evello Featured By Owner Jun 16, 2014  Student General Artist
Ugh I remember studying cells in like... Ninth grade... That was awful. XD
I loooved doing all the genetic projects though that was a ton of fun
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 16, 2014  Hobbyist General Artist
Lol it doesn't get any better in university. They just go into more detail. *dies*

Me too^^ I enjoy doing the 'genetics' part of it, but I've discovered that mainstream molecular genetics is not where I want to go. (Ie, biology of the cell stuff.)
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:iconevello:
Evello Featured By Owner Jun 16, 2014  Student General Artist
I don't think I could ever go to school for genetics XD too much other stuff you have to learn that I hate. Like science. XD

But it is really useful for harpg isn't it? =D
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 16, 2014  Hobbyist General Artist
xD yeah... a lot of science. Like chem >.>

Haha it can be, most definitely.^^
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:iconevello:
Evello Featured By Owner Jun 16, 2014  Student General Artist
Chemistry
The pain
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 16, 2014  Hobbyist General Artist
Agreed...
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:iconsmexyhajisan:
SmexyHajiSan Featured By Owner Jun 16, 2014  Hobbyist Digital Artist
TEACH ME BAE
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 16, 2014  Hobbyist General Artist
LOL. I sorry.. I had to get it out... It drives me bonkers.
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:iconsmexyhajisan:
SmexyHajiSan Featured By Owner Jun 16, 2014  Hobbyist Digital Artist
Nah that was really helpful actually. I'm sure other people will benefit from it, no doubt. Genetics are always the hardest.
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 16, 2014  Hobbyist General Artist
That's good... I linked an older, more in depth journal that had a shorter description of the differences, but a lot more on how it all works together as well...

Genetics is difficult, but if you can visualize it, it is so freaking cool. Lol. Theres a lot of little stuff harpg does that isn't techically the 'right' way to show a genotype, but I can see it being easier.  But this can get into being a big confusing issue because it's two different things.

The hardest part would be to change the nord community to get them to stop using Dom to describe their mutation alleles.. xD I doubt that's ever going to happen.
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:iconsmexyhajisan:
SmexyHajiSan Featured By Owner Jun 16, 2014  Hobbyist Digital Artist
Si. Well, hopefully things will get easier for people and I hope my terrible genetics knowledge doesn't hurt your eyes X3.


Nords... Nords will never change...


Speaking of genetics, would you like to help me come some for a new breed? Its a cat breed, btw, because when I was doodling design linearts to sell for points I sort of wandered off track and it evolved into a breed.
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:iconathenamyth:
AthenaMyth Featured By Owner Jun 16, 2014  Hobbyist General Artist
Hopefully. ^^ Theres a ton of info on here, by enthusists and those who study it. It's just making sure that the info you're reading is actually correct and they have researched it/know what they're talking about.

Pft, no. I'd point it out if it really bothered me. xD

Sure! I'd love to do that.^^ Just shoot me a note and tell me what you want me to do. :D Don't you love when that happens?
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:iconsmexyhajisan:
SmexyHajiSan Featured By Owner Jun 16, 2014  Hobbyist Digital Artist
Ve~ Of course. I'm going to put up the breed sheet first.
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