Cross 5
Purpose: Backcross 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)
Female (C3AF):
Gandalf’s daughters from Cross 3 (I used 6 total females).
Strain: Half Snow-White
Relevant genes. Some are assumptions, indicated with italics. Although their decedents strongly support the claims:
Base body color: Gray (bb)
Magenta: likely (Mm)
European Blau: (Rr)
Stoerzbach: (Ss)
Offspring:
Born: Several Batches between October 10, 2023 and November 11, 2023. I lost track of the exact dates
Brood Size: 70
32 Male
38 Female
Offspring phenotypes:
Males:
Group A: The typical Snow-White phenotype. Shown on the top left of the figure. (4 males).
Group B: Similar to the Snow-White phenotype but with a yellow-ish tail and less topside iridescence. Shown on the bottom left of the figure. (14 males).
Group C: No Snow-White coloration with mostly red pigmentation. Elevated levels of body iridescence that transitions to topside and caudal iridescence. This tends to make the guppy look almost pink sometimes. Shown on the top right of the figure. (3 males).
Group D: Similar to group C but with significantly less iridescence where it is almost absent on their topsides. These guppies appear more red than pink. Shown on the bottom right of the figure. (11 males).
Females: I could not really tell the difference between females that had red tails that also expressed stoerzbach. I did notice a slight difference in body color though. There were some females that had a yellower look to them. This was very hard to capture on camera though. This led me down the path of looking into difference blau genes. This could potentially be due to stoerzbach but I am doubtful. I get into that a bit more below.
Group A: Females that lacked red pigmentation but had visible white color on their tails. (9 females).
Group B: Females with neither red or white pigmentation. (20 females).
Group C: Females that expressed some red pigmentation. (9 females).
Phenotypical distribution as a percentage for just the males following the A:B:C:D group order: [12.5 : 43.8 : 9.4 : 34.4] .
And the females: [23.7 : 52.6 : 23.7]
Likely genotype(s) following the order of the listed genes for the parents:
Males:
Group A: bb|(MM or Mm)|rr|ss
Group B: bb|(MM or Mm)|rr|Ss
Group C: bb|(MM or Mm)|Rr|ss
Group D: bb|(MM or Mm)|Rr|Ss
Females:
Group A: bb|(MM or Mm)|rr|ss
Group B: bb|(MM or Mm)|rr|(Ss or ss)
Group C: bb|(MM or Mm)|Rr|(Ss or ss)
Notes:
The C5A females should automatically have at least one magenta allele because their father was Gandalf who is presumably homozygous for magenta.
This cross marked the beginning of my exploration into the potential involvement of a Blau gene. I noticed a subtle difference in the body color of the females: roughly half displayed a slightly lighter, more transparent hue compared to their yellower sisters. While several Blau genes are listed in genetic references, European Blau seemed the most plausible fit. It's an autosomal recessive gene, denoted by the letter 'r'. From this point on, I've assumed any offspring showing any red coloration are not expressing European Blau and are likely carriers of the recessive allele (at least in most of my cases).
I did consider whether these body color variations were due to differences in homozygous or heterozygous Magenta or stoerzbach genotypes, rather than European Blau. While the numbers alone offered some support, the resulting phenotypes didn't align with that hypothesis. I delve into this reasoning in much greater detail in my video.
The phenotypic distribution among the male offspring doesn't align with the expected 25 : 25 : 25 : 25 ratio for a cross involving two autosomal genes, specifically when crossing a heterozygous to a homozygous genotype. The genes in question are European Blau and stoerzbach. I’ve excluded blond and magenta from consideration, assuming identical color phenotypes for MM and Mm genotypes. Instead of the anticipated 25% distribution across all four phenotypic groups, there is a disproportionately larger percentage in groups B and D. These are the groups I initially categorized as not expressing stoerzbach. My strict classification, however, may be skewing the results: I only counted a male as having stoerzbach if its iridescence extended into his topside. The likely issue here is that topside iridescence might be controlled by a separate gene. Despite this, finding a clear, consistent distinction between stoerzbach and non-stoerzbach phenotypes has proven challenging, so I'll maintain this classification convention for now. Interestingly, if group B in the females is split in half, the distribution reflects the expected 25% distribution across the board.
I selected two males from group A as breeders for the next set of crosses.
The first male was paired with a few females from Cross 6 to establish Cross 11. This male was labeled Cross 5 Male A (C5AM).
The second male was paired with a few females from Cross 7 to establish Cross 12. This male was labeled Cross 5 Male B (C5BM). B because he is the second male I am using from this cross.
A YouTube Video detailing the start of this cross can be found here.
C5AM
C5BM
I kept a few males around without any plans of breeding them before giving them away. I added a few photos to show how they matured. Granted one of them is not the best quality.
The first one is of a yellow tailed male from group B. The photo was taken on June 10th 2024 (~8 months old). This is an interesting phenotype and would be nice to revisit someday.
The second one is of a red tailed male from group D. The photo was taken on November 11, 2024 (~ 1 year old). I noticed he also had some yellow in his tail. He looks like a tequila sunrise and could be hinting at the origin of the original female #3 used in Cross 3.
