Genetics

Betta fish color variation is based on the color pigmentation in different types of cells. These color cells are in layers within the skin. In the bottom-most layer are the xanthophores which produce a yellow color. The next layer of pigmented cells are the erythrophores, which produce the red color. On top of these are the melanophores which produce the black color. Finally, on the top-most layer are guanophores (iridophores) which produce the green and blue iridescent colors. These different types of cells have groups of traits associated with them. For example, the erythrophores (red cells) have the extended red trait (red covering the whole body and fins), the non-red trait (the complete absence of red) and the wild-type trait (erythrophores covering portions of the pelvic, anal and caudal fins and parts of the body). These traits are determined by the genes of the fish.

Some of the genetics are characterized, however the characterization is not very well defined. For most biosynthetic pathways a group of genes encode for the enzymes which catalyze a series of reactions to produce a specific pigment. For example:

gene A --> enzyme A
gene B --> enzyme B
gene C --> enzyme C

Pigment Biosynthetic Pathway
enzyme A
compound 1 ---> compound 2
enzyme B
compound 2 ---> compound 3
enzyme C
compound 3 ------> Pigment

If any genes in the pathway were mutated such that an enzyme no longer worked, the pigment would no longer be produced. This may be the case for the non-red trait. However, the extended-red trait is likely due to an expression of a functional protein involved in the regulation of the entire pigment biosynthetic pathway. In other words the pigment biosynthetic pathway can be turned on or off by protein "switches" in different parts of the fish. These "switch" proteins (regulatory proteins) can either work to "turn on" genes in specific regions of the fish or can work to "turn off" the genes, depending on where they are in the fish as would be seen in a trait like the butterfly trait. Additionally these regulatory proteins can also be influenced by external stimulus (water conditions, feeding or during spawning).

So traits (also known as phenotypes) are what we see and the genes that make up the traits (also known as genotypes) contain the information for the proteins that catalyze the reactions to produce the pigment we see. It can be very complicated, and when breeding fish outside of an established strain--anything can happen!

The Known Betta Traits

BLACK
Cambodia (c)	Light Body Dark Fins	Resessive Gene	cc=Cambodia +c & ++ = Wild type
Blond (b)	Reduced black	Resessive Gene	bb = Blond +b & ++ = Wild type
Melano (m)	Excessive Black Sterile Females	Recessive Gene	mm=Melano +m & ++ = Wild type
marble(yes)	Black and white patches under other colors	non-mendalian genetics	yes/no-maybe ;) ****
Red
Non-Red (nr)	No red pigment associated with whites and yellows	Resessive Gene and multiple genes	nr nr = Non-Red +nr & ++ = Wild type
Variegated fins (Vf)	Streaks and patters in the fins butterfly trait	Dominant gene	Vf+ & VfVf = Variegated ++ = Wild type
Exstended Red (Er)	Red covering all fins and body	Dominant Gene	Er+ & ErEr = Extended Red ++ = Wild type
Iridocyte Color
No-Iridocyte ??	No sheen, seen in pure red fish	??	??
Blue (bl)	The Blue, Green or Gun blue sheen	Incomplete Dominance	++ = Green, bl+ = Royal Blue blbl = Gun Blue
Spread Iridocytes (Si)	Increased distribution of Blue	Dominant Gene	Si+ & SiSi = Spread Iridocytes ++ = Wild type
Pastels
Opaque (Op)	Whitish glaze on top of the color	Incomplete Dominant Gene	OpOp = Opaque Op+ = less Opaque ++ = Wild type
Tail shape
Veil-tail (P)	Long flowing tails	Dominant Gene	P+ & PP = Veil-tail ++ = short tail
Double-tail (dt) or Split-tail	2 lobes to the tail Enlarged dorsal fin	Resessive Gene some incomplete dominance of the single tail trait mostly seen as an increase in fin rays of the dorsal	dtdt = Double-tail +dt & ++ = Wild type
Combtail (p)	Extended fin rays Past the webbing	Resessive Gene	pp = Combtail +p & ++ = Wild type
Crown tail	Extended fin rays 30-50% past the webbing	non-mendialian genitics	yes/no-maybe ;) ****
Giant (Gi)	over production of fish growth hormone	Incomplet Dominance	Gi+ = 3+ inches GiGi = 7+ inches
Behavioral trait
Fighters (f)	An agressive nature	Resessive gene	ff = fighter +f & ++ = Wild type
Unknown or a mixture of traits
white, half-moon = ???

Traits can often be predicted using a Punnett Square. For example if you cross two Royal blue fish(+,bl). Each will have 2 copies of the genes to make up their traits. When they make sperm and egg cells they only pass one copy, either (+) or (bl). So you set up a punnett square like this:

The Punnett Square

	male sperm (+)	male sperm (bl)
female egg (+)	green fish (+,+)	Royal blue fish (+,bl)
female egg (bl)	Royal blue fish (+,bl)	Gun blue fish (bl,bl)

That is 50% Royal blue fish, like the parents, 25% green fish and 25% Gun blue fish in the f1 generation.

Taken from A Complete Authoritative Guide Siamese Fighting fish
by Gene A. Lucas, Ph D. ISBN 0-7938-0120-6
Updated by an artical by Gene Lucas in Flare Vol 33 No.3 Nov-Dec 1999. An IBC Publication.
http://www.bettysplendens.com/articles/page.imp?articleic=725
He also sugested the following book to learn genetics.
A Survey of Genetics (1989, ISBN 0-536-57462-6, BA 5122) By Dr. Wilmer J. Miller.

**** Leo Buss - personal communications (as I interpreted it)