Thank you to my french partner in crime from Canada, Tania, for some of her beautiful photos! <3 <3 She is based in Laval Canada for those of you not in the USA who would like some wonderful pet rats!
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If you have a specific color you are looking for hit "Ctrl F" on your keyboard and type in the color to the box that appears, if it is not here you can ask me in a personal message at Facebook.com/RatsAreBeautiful to add in the color or to ask more specific questions about the listed information. To close the search window that appears when you hit "Ctrl F" there should be an "x" button.
Chromosomes in Humans and Rats:
-Every animal has a different number of Chromosomes. We all get one chromosome from our mom and one from our dad in each pair. Bacteria and simple species that divide rather than reproduce with male and female simply make copies of themselves as their offspring. Chromosomes are thread-like structures located in the brain, or nucleus of every plant and animal cell. They are made up of protein and a single molecule of DNA, or deoxyribonucleic acid. The center or part where each individual chromosome indents, is called the centromere, and the ends are called telomeres. Centromere help the chromosome when it divides, which is a whole other lesson.
-Every animal has a different number of Chromosomes. We all get one chromosome from our mom and one from our dad in each pair. Bacteria and simple species that divide rather than reproduce with male and female simply make copies of themselves as their offspring. Chromosomes are thread-like structures located in the brain, or nucleus of every plant and animal cell. They are made up of protein and a single molecule of DNA, or deoxyribonucleic acid. The center or part where each individual chromosome indents, is called the centromere, and the ends are called telomeres. Centromere help the chromosome when it divides, which is a whole other lesson.
-Humans have 46 chromosomes, 23 from dad and 23 from mom. One of a human's 46 pairs is their sex pair. The sex chromosomes are XX for females and XY for males. There are mutations that can make a person have strange chromosomes. like trisomy 21, or down syndrome, where the human has one extra chromosome in the 21st pair.
The Y gene, in males only, contains a gene called the SRY gene. This determines that the male is a male. Animals and humans can even have strange sex chormosomes like a female having an extra X chromosome, missing an X or even having a Y that only males are supposed to have. Most of these sex chromosome problems make the animal sterile, or unable to have children. Rats have 42 chromosomes so 21 pairs and one pair of those 21 pairs is their sex pair, just like ours. |
Dominant genes vs Recessive genes:
-Think of dominant as, "the strong one", it is shown by an uppercase letter. "Dominant = large, too heavy and can't be carried". Carried means the trait does not show up, but the rat or other species can pass the gene onto their children. These "carried" genes are called recessive. "Recessive = weaker, light and can be carried". These genes are showed by a lowercase letter. So, with a recessive gene you will have rats that either have the gene or carry it, while a dominant gene either shows up or it is not there.
-An example are the base colors of all rats agouti which is a dominant gene and black which is a recessive gene. Every rat is either agouti or black based. Agouti and black share the same genetic letter. "AA" is the homozygous dominant gene and it is agouti. Homo means same, and as you can see "AA" is two of the same uppercase letters, or two dominant agouti genes. A homozygous dominant agouti base rat can not make black base rats, it will only make more agouti.
-The black color is the Homozygous recessive gene represented by two lowercase letters "aa". When paired with a black rat the rat will become- "Aa", which is a Heterozygous dominant gene, hetero means different. This means that these rats when paired with black rats can have both black or agouti rats. A- is used if we do not know whether a rat that is Aa or AA. Both of these are agouti, except that Aa agouti "carries" one black gene "a".
Any colors that are not Agouti or Black are called dilutes, but, as states previously, every color is either agouti or black based. RED, red eye dilute "rr" , and PED, pink eye dilute "pp", are a little different, because with RED or PED the rat's eye color lightens their fur color. These dilutes are like bleach, turning the fur to an orange tint.
Modifiers are written above the genetic letters or between parenthesis example H(i)H(i) is double irish, the (i) is the irish modifier, double irish is self HH, a homozygous dominant gene, with two irish modifiers.
-Below are some of the genetic code notes I have picked up over my years studying rat genetics in chart form so it is easier to read. Because there is so little information on rat genetics online, and so much different information depending on where you look, I did my best to come up with the most accurate information I could while researching. Markings are extremely complex and some marking genetics (not listed) are still just theory so I am only getting into them briefly here and I go more into depth with colors. For any questions, suggestions, or concerns on the information listed below ask me on our facebook page listed in the Contact Information tab.
-Think of dominant as, "the strong one", it is shown by an uppercase letter. "Dominant = large, too heavy and can't be carried". Carried means the trait does not show up, but the rat or other species can pass the gene onto their children. These "carried" genes are called recessive. "Recessive = weaker, light and can be carried". These genes are showed by a lowercase letter. So, with a recessive gene you will have rats that either have the gene or carry it, while a dominant gene either shows up or it is not there.
-An example are the base colors of all rats agouti which is a dominant gene and black which is a recessive gene. Every rat is either agouti or black based. Agouti and black share the same genetic letter. "AA" is the homozygous dominant gene and it is agouti. Homo means same, and as you can see "AA" is two of the same uppercase letters, or two dominant agouti genes. A homozygous dominant agouti base rat can not make black base rats, it will only make more agouti.
-The black color is the Homozygous recessive gene represented by two lowercase letters "aa". When paired with a black rat the rat will become- "Aa", which is a Heterozygous dominant gene, hetero means different. This means that these rats when paired with black rats can have both black or agouti rats. A- is used if we do not know whether a rat that is Aa or AA. Both of these are agouti, except that Aa agouti "carries" one black gene "a".
Any colors that are not Agouti or Black are called dilutes, but, as states previously, every color is either agouti or black based. RED, red eye dilute "rr" , and PED, pink eye dilute "pp", are a little different, because with RED or PED the rat's eye color lightens their fur color. These dilutes are like bleach, turning the fur to an orange tint.
Modifiers are written above the genetic letters or between parenthesis example H(i)H(i) is double irish, the (i) is the irish modifier, double irish is self HH, a homozygous dominant gene, with two irish modifiers.
-Below are some of the genetic code notes I have picked up over my years studying rat genetics in chart form so it is easier to read. Because there is so little information on rat genetics online, and so much different information depending on where you look, I did my best to come up with the most accurate information I could while researching. Markings are extremely complex and some marking genetics (not listed) are still just theory so I am only getting into them briefly here and I go more into depth with colors. For any questions, suggestions, or concerns on the information listed below ask me on our facebook page listed in the Contact Information tab.
Inbreeding and Out Crossing:
Inbreeding is breeding within a family, out crossing is breeding out side a family.
Rats in the wild each have packs. In these packs they are all family. Although a lot of lines start with out crossing to get the health, temperament, and looks going in a line, inbreeding after that keeps the genes going that benefit that line. Out crossing at that point is dangerous and defeats the purpose of the line, unless the line is broken off to become two or three separate lines. However, to improve a line it is easiest to stay inline and be selectively bred for the best results. Any health issues in a line should be bred out, and out crossing into a well established line can bring sickness in after a few litters.
You could do it either way if you know the background of every rat. However, out crossing into a well established line can be dangerous and bring in sickness to the line. It is easier to selectively breed when each rat has the traits to improve the line and it is easier to know their backgrounds when they have the same background. Which works best for rats because they inbreed naturally in the wild.
Inbreeding is breeding within a family, out crossing is breeding out side a family.
Rats in the wild each have packs. In these packs they are all family. Although a lot of lines start with out crossing to get the health, temperament, and looks going in a line, inbreeding after that keeps the genes going that benefit that line. Out crossing at that point is dangerous and defeats the purpose of the line, unless the line is broken off to become two or three separate lines. However, to improve a line it is easiest to stay inline and be selectively bred for the best results. Any health issues in a line should be bred out, and out crossing into a well established line can bring sickness in after a few litters.
You could do it either way if you know the background of every rat. However, out crossing into a well established line can be dangerous and bring in sickness to the line. It is easier to selectively breed when each rat has the traits to improve the line and it is easier to know their backgrounds when they have the same background. Which works best for rats because they inbreed naturally in the wild.
Fur:
Rex fur is a co-dominant gene. This means it shared dominance with double rex.
ReRe = Double Rex Rere = Rex rere = Standard There is a double velveteen fur type also. There is speculation to weather they are both rexoid genes that have branched off into separate genes. Although the fur types are very similar, rex is very rough and more tightly curled, while velveteen is softer and less curly. Also double velveteens have a bit more fuzz to them usually and the fuzz is much softer than the rough fuzz on a double rex. Most lines of velveteen lose their curl when they become adults. I am not sure how to write it, since the genetics for standard are usually written in context with rex as "rere". And velveteen is written as "cucu". There has been argument on whether "true" velveteen is recessive or co-dominant like rex, or if the co-dominant "velveteen" is simply just another rexoid gene. However, there are MANY rexoid genes, giving a range of thick curls to light waves. Hairless is a recessive gene which separates it from rexoid genes. They normally have a lot less whiskers than rex or no whiskers at all. They can have a little peach fuzz but are normally just skin whereas double rex and double velveteen have a light fuzz all over their bodies that is heavier in some areas and usually changes through their lives. There are many theories on what letters to use to represent the hairless gene, the most common is "fufu" or fuzz. Hairless can have many skin and eye problems which are majorly heightened when two are bred together. NEVER breed two hairless rats together. If we use fufu then hairless would be written as: refu = Standard carrying hairless fufu = Hairless rere = Standard |
Colors:
Pearl: Pepe, Merle: Me- and lethal PePe
A-mmPepe = Cinnamon pearl aammPepe = Pearl A-M-Pepe = Agouti rat carrying pearl aaM-Pepe = Black rat carrying pearl A-mmMe-Pepe = Cinnamon Merle aammMe = Mink Merle aammMe-Pepe = Pearl Merle Merle can only show up on mink based colors like pearl. Any rat with PePe in their genetic code will not be born, PePe is lethal. pepe and meme are not genes. |
Chocolate: bb
aabb = Chocolate
A-bb = Chocolate Agouti
A-bbdd = Russian Chocolate Agouti
aabb = Chocolate
A-bb = Chocolate Agouti
A-bbdd = Russian Chocolate Agouti
pp and rr genes:
A-rr = Fawn aarr = Beige A-Rr = Agouti carrying RED aaRr = Black carrying RED RR is not a gene. A-pp = Amber aapp = Champagne A-Pp = Agouti carrying PED aaPp = Black carrying PED PP is not a gene. RED rr and PED pp Chart: RED: Mink carries RED = Havana Mink Mink has RED = Similar to a beige Blue carry RED = Blue Blue has RED = Type of platinum Black has RED = Beige Black carry RED = Black Agouti has RED= Fawn Agouti carry RED = Agouti PED: Mink carries PED = Mink Mink has PED = Champagne mink Black carries PED = Black Black has PED = Champagne Blue carries PED = Blue Blue has PED = silver Agouti carries PED = Agouti Agouti has PED = Amber |
A few double dilutes:
aaggmm = Platinum A-ggmm = Platinum Agouti aaGgmm = Mink carrying American blue A-Ggmm = Cinnamon carrying American blue aaggMm = American blue carrying mink A-ggMm = American blue agouti carrying mink A-ggrr = Platinum Agouti aaggrr = Platinum (AB) aaggpp = Silver A-ggRr = American blue agouti carrying RED aaggRr = American blue carrying RED A-Ggrr = Fawn carrying American blue aaGgrr = Beige carrying American blue aaddrr = Platinum (RB) aaggdd = Russian silver A-ggdd = Russian silver agouti aaddmm = Russian dove A-ddmm = Russian cinnamon GG, DD, and MM are not genes. |
cc Gene and (h) Modifier:
A-cc = Albino aacc = Albino A-Cc = Agouti carrying albino aaCc = Black carrying albino A-c(h)c(h) = Agouti point Siamese aac(h)c(h) = Seal point Siamese A-Cc(h) = Agouti carrying Siamese aaCc(h) = Black carrying Siamese A-cc(h) = Agouti Himalayan aacc(h) = Himalayan BuBu c(h)c(h) = Siamese sable Burmese BuBu cc(h) = Himalayan sable Burmese BuBu cc = Burmese sable with no Point Bubu c(h)c(h) = Siamese Burmese Bubu cc(h) = Himalayan Burmese Bubu cc = Burmese with no Point A-BuBu c(h)c(h) = Wheaten Siamese sable Burmese A-BuBu cc(h) = Wheaten Himalayan sable Burmese A-BuBu cc = Wheaten Burmese sable with no Point A-Bubu c(h)c(h) = Wheaten Siamese Burmese A-Bubu cc(h) = Wheaten Himalayan Burmese A-Bubu cc = Wheaten Burmese with no Point bubu is not a gene. Himalayan Burmese is also called biscuit cream. aaggc(h)c(h) = Blue Point Siamese aaddc(h)c(h) = Russian Blue Point Siamese aammc(h)c(h) = Mink Point Siamese CC is not a gene. cc is a gene that covers up all color and markings. Without knowing a rat's background you can't know what marking or color they are for sure. -To make only himalayan in a litter one would breed a safe cc to a siamese. -Two himis can also make albino, himi, or siamese, because they can give any combination of the c and c(h) genes. -However, siamese can never make cc because they can only give a c(h) gene. |
Markings:
Simple Markings Chart:
Irish + Self = Irish and Self Berk +Self = Berk and Self Hood + Self = Berk Double Irish + Self = Irish Double Irish + Berk = Self and Irish Irish + Irish = Double Irish Double Irish has two irish modifier genes and Irish has one irish modifier gene. Double Irish looks berk but does not breed like berk. Simple Markings: Hooded, Self and, Berkshire are the base markings. All of the other markings are modifiers on the base markings. hh = hood HH = Self Hh = Berkshire -Hooded has color in a hood like pattern that comes around the face down the shoulders then stops. Another noticeable hooded trait is the line of color straight down the spine. -Self has no white anywhere on the body. -Berkshire is full color with a white belly and white feet. |