Goldfish (confirmed introduction)
Goldfish have various body colors, which are composed of black pigment cells, orange-yellow pigment cells and light blue reflective structures. Due to the recombination of these three factors, the number and differentiation of various pigment cells, as well as the number and concentration or differentiation of pigments, etc., can change their appearance, so the color of the fish body changes. These traits are hereditary .
There is a kind of goldfish that is dark blue all over, called blue fish. There are different types of blue fish, such as blue dragon eye, blue head, blue bubble, and blue phoenix. Another type of fish with a face color between dark brown and brown is commonly known as purple fish. There are also different types of purple fish such as purple dragon eyes, purple tuna, and purple pearls.
All the descendants of blue fish obtained during self-grafting are blue, which proves that the blue fish are not separated and are pure breeds. When blue fish and gray fish (wild crucian carp) are connected forward and backward, the resulting offspring will have the same gray color as crucian carp. This indicates that gray is dominant (the trait of a certain parent that is shown in the first generation of the hybrid is called dominant), and blue is recessive (the trait that is not shown by the parent in the first generation of the hybrid is called dominant) The offspring obtained from the self-crossing of the recessive human purple fish are all purple, which proves that the purple fish is not separated and is also a pure breed. The offspring obtained from the hybridization of the blue fish and the purple fish do not produce blue and purple, but a combination. Dark gray and black. There are 4325 non-blue fish and 1383 blue fish in the second generation of hybrids obtained from the first-generation brother-sister mating. The ratio between them is 3:1. The results show that the blue color of goldfish is controlled by a pair of recessive genes. The wild-type allele is dominant. When it exists, gray, black or other non-blue colors will occur.
When hybridized with crucian carp, the resulting offspring are all gray, which is the same color as crucian carp. It seems that purple is also recessive. When hybridized with purple fish, most of the next generation produced is gray. (267 fish), while the number of purple fish is only a very small number (189 fish), which is consistent with the ratio of 15:1. Therefore, it may be that purple is controlled by 4 pairs of genes, and only 4 pairs of genes are recessive and homozygous. , can it develop into purple (aabbccdd). If all four dominant alleles are involved, the color of the fish will develop into gray, black or non-purple. Direct and reverse connection test of purple fish and non-purple fish. Similar results were obtained, proving that these 4 basicBecause it is not sexually inherited.
A kind of homozygous purple-blue goldfish species that is produced by the hybridization of blue fish and purple fish. This fish is controlled by 5 pairs of recessive genes.
The inheritance of other body colors is also a very interesting issue in genetic experimental research, and it is also very complicated. Because in the individual development process of goldfish, fading often occurs. The juvenile stages of various goldfish are almost the same. They all have a grayish-brown color, which is transformed into the body color of adult fish due to the partial loss of pigment cells. Black goldfish produce black color due to the reduction of black pigment cells, which often fades to orange-red within 2 to 3 years. This fading property is dominant to the non-fading property of ink. Red goldfish are often spread out in white. The central state of these fading processes produces mottled goldfish.
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