Cross 4

Snow white and Halfblack or Moscow black crossbreeding

Purpose: The fourth deliberate outcross to begin the program to restore the snow white phenotype.

Male (Gandalf):

  • Bought from a big box store during February 2023 as part of the initial stock.

  • Strain: Snow White

  • Relevant genes. Some are assumptions, indicated with italics. Although their decedents strongly support the claims:

    • Base body color: Blond (bb)

    • Magenta: likely homozygous (MM)

    • European Blau: (rr)

    • Stoerzbach: (ss)

    • Nigrocaudatus: (XⁿᶦᴵY)

Female (Female #4):

  • Bought from a big box store during February 2023 as part of the initial stock.

  • Strain: Unknown but maybe a black moscow

  • Relevant genes. Some are assumptions, indicated with italics. Although their decedents strongly support the claims:

    • Base body color: Gray (BB)

    • Magenta: likely a non-carrier (mm)

    • European Blau: (RR)

    • Stoerzbach: (SS)

    • Nigrocaudatus: likely homozygous (XᴺᶦᴵXᴺᶦᴵ)

Results of snow white and halfblack or moscow black guppy crossbreeding

Offspring:

  • Born: August 11, 2023

  • Brood Size: 54

    • 31 Male

    • 23 Female

  • There was just one phenotype:

    • All the males and females looked like the ones in the figure. The females were duller but likely the same as the males in terms of their color. These females also looked very similar to the female offspring in Cross 1 with maybe a darker halfblack and a more vibrant red color. The males were halfblack reds and also very similar to the halfblack red offspring in Cross 1. A very uniform result.

  • Likely genotype(s) following the order of the listed genes for the parents:

    • Bb|Mm|Rr|Ss|(XᴺᶦᴵXⁿᶦᴵ or XᴺᶦᴵY)

  • Notes:

    • I initially did not know if the female was homozygous or heterozygous for the gray-based body color. Because all of the offspring were gray-based, this suggests that female #4 was homozygous for gray-based body color.

    • I initially did now know if the female carried the magenta gene or not. It seemed safe to assume that she didn’t because magenta looks to be an incompletely dominant gene and I could not find any signs that she expressed magenta.

    • European blau was a gene I only became aware of during Cross 5 but it seems to be important in these crosses. I’m not 100% convinced that it is European Blau but so far, the data seems consistent.

    • With all the offspring expressing the halfblack characteristic, this suggests that female #4 was homozygous for it. There are two versions of this gene and I am assuming that Nigrocaudatus I is the one responsible here and is carried on the X chromosome.

    • Two of the halfblack red females were used to backcross to Gandalf (Cross 9). These females are labeled Cross 4 Female A (C4AF).

    • A YouTube video detailing this cross can be found here.

Halfblack red result of crossbreeding a snow white and halfblack moscow guppy

  • As the males aged, their fins grew larger. See the male pictured above. This was taken June 1st, 2024. Just shy of a year old. The halfblack red males from Cross 1 also matured to look very similar. This makes me think that a single copy of the magenta gene does not reduce fin size.