Angelfish definitions

[Mugwump]

Genes: Where the genetic information is carried or stored and they are located on a specific locus on a chromosome. Chromosomes always come in pairs with one coming from each parent.

Alleles: They are the different variations or mutations of a gene that can occur at a specific locus. A good example would be the dark locus which carries the following alleles. They are Dark (D), Gold Marble (Gm), New Gold (g), and Marble (M) as well as Wild Type (+).

Genetic Code: (Sm) The designation that represents the gene.

Locus/Loci: Sm/+ or +/g Where the two genes/alleles are located. Each parent supplies one of the two.

Genetic Notation: (Sm/+-S/+-+/g-+/?-p/p) Where all the loci involved in the phenotype/genotype are stated for any angelfish.

Phenotype: The expression or appearance that the fish is named for such as Gold Marble, Marble, Smokey.... In some cases the phenotype name and the genotype name are the same such as Gold Marble. In the case of fish which have multiple loci involved like the Smokey Marble (M/+-Sm/+) the expression may determine the name or it may not such as Turquoise Blushing (D/+-S/S).

Genotype: The genetics that make up an angelfish such as Double Dark Black (D/D) or Gold Marble Blushing (Gm/Gm-S/S) or (Gm/g-S/S).

Epistatic: The complete dominant expression seen between two genes one over the other located on different loci. A double dose of New Gold (g/g) hides Smokey (Sm), Zebra (Z), and Half Black (h) completely. So we would say that New Gold is epistatic to Smokey, Zebra, and Half Black in double dose.
http://www.theangelfishsociety.org/p...ivos/frame.htm

Homozygous: A trait/expression that is determined by a double dose of the same gene/allele at the same locus. New gold would be a good example since it is a recessive gene. The fish would only express as a New Gold in double dose (g/g) and would therefore be homozygous for New Gold (g). The same would apply to Half Black (h/h), Albino (a/a), or Double Dark Black (D/D) though it does express in single dose. They would all be homozygous for the gene/allele. Homozygous fish of the same genotype would breed 100% true so long as there are no recessive genes/alleles hidden that would become epistatic in double dose.

Heterozygous: A trait/expression that is determined by a single dose of two different genes/alleles at the same locus. Black Lace (D/+) would be a good example. We would say the fish is heterozygous for Dark (D) and heterozygous for Silver/Wild Type (+). Heterozygous fish do not breed true. In the case of Black Lace (D/+) you would get Double Dark Black (D/D), Black Lace (D/+), and Silver/Wild Type (+/+) from a pair.

Dose: A term used to represent the gene/allele supplied by a parent. An example would be in the case of Black Lace one parent supplied the Dark gene (D) and the other parent supplied the Silver/Wild type gene (+).

Hybrid as it is used in regard to angelfish: A trait/expression that is created by two different genes/alleles. A hybrid angelfish would be heterozygous for both genes involved and therefore would not breed true. However a percentage of the fry produced would be homozygous and would breed true. Once again using Black Lace (D/+) as an example a pair would produce Double Dark Blacks (D/D), Black Lace (D/+), and Silver/Wild type. You would have two types of homozygous fry produced those being Double Dark Black (D/D) and Silver/Wild Type (+/+) and using those you could form true breeding pairs.

Recessive: A gene is recessive when it and another allele share the same locus and it is not expressed (completely hidden) in single dose by the other allele. New Gold (g) is a good example because in single dose it is hidden by all of its alleles which are Dark (D), Marble (M), Gold Marble (Gm), and Silver/Wild Type (+).

Dominant: A gene is dominant when it and another allele share the same locus and it completely hides the expression of the other allele. An example would be Dark (D) is dominant over New Gold (g) because it completely hides New Gold (g) in a Black (D/g) angelfish.

Incomplete Dominant or Co-Dominant: A gene acts as an incomplete dominant or co-dominant when it and another allele share the same locus and there is a blending of the traits cause by the two alleles. A Silver Gold Marble (Gm/+) would be a good example where you see the stripes of a Silver/Wild Type and the marbling of a Gold Marble (Gm) combined in the heterozygous fish produced. In this situation both Gold Marble and Silver/Wild Type (+) act as incomplete dominants of each other.

Mutation: A mutation is what gives us the new genes/alleles we have to work with such as Dark (D), Gold Marble (Gm), Marble (M), and so on. It is an instant permanent change in genetic material which creates the new gene/allele. Anything other than Silver /Wild Type (+) is a mutation including the modifiers such as Stripeless (S) or Streaked (St) and the fin mutations such as Veil (V). You can tell by the limited number recognized that major mutations do not happen often.

Caudal Penduncle: The point where the cadual fin attaches to the body of the fish.

[BallAquatics]

If you are interested, there is a FREE course about genetics from the University of British Columbia starting next week.

More info here ==>> https://www.coursera.org/course/usefulgenetics

Dennis

[Mugwump]

Thanks....looks interesting

[Frank The Plumber]

He he he. I dig her hair color.

[BallAquatics]

He he he. I dig her hair color.

That's what thinking about quantitative trait locus analysis all day does to you  LOL

Dennis

[Frank The Plumber]

The beautiful thing about genetics is that nature is intentionally not perfect. She makes errors. In making errors she allows variations to her rules and life's details develop if it survives with these errors.

If you push her closer to the edge you may get her to make mistakes a little more frequently. If you can isolate that one in 5 million mistake it can be mundane or it can be spectacular.

[Mugwump]

The beautiful thing about genetics is that nature is intentionally not perfect. She makes errors. In making errors she allows variations to her rules and life's details develop if it survives with these errors.

If you push her closer to the edge you may get her to make mistakes a little more frequently. If you can isolate that one in 5 million mistake it can be mundane or it can be spectacular.

Yep...look at me...I'm one in 250 billion....LOL

[BallAquatics]

It helps a lot too, that we can protect natures mistakes in the controlled environment of the aquarium. 

Dennis

[Mugwump]

It helps a lot too, that we can protect natures mistakes in the controlled environment of the aquarium. 

Dennis

That's true.....it does give us an advantage....the hard part can be recognizing some of the subtle differences in small fry, that are not developed enough to reveal their treasures...

[BallAquatics]

....the hard part can be recognizing some of the subtle differences in small fry, that are not developed enough to reveal their treasures...

That's what goes through my head every time I'm culling fish.....  If we could just raise them all..... how many of those slow developing fish could have been a real stunner when mature???   

Dennis

[Mugwump]

Agreed....there can sometimes be a diamond in the rough....and we'll miss it...