Characters are maintained by genes. What are genes? The many segments contained in chromosomes are called genes or genetic factors. Each gene "reveals" a specific characteristic of the body. For example, some genes are related to the color of a cat's coat, while others are related to the quality of the coat. There are also genes related to the size of various parts of the body, the function or behavior of internal organs. Cats pass their traits to the next generation through genes, and there are many interesting situations in cat genetics that are worthy of our understanding.
According to overseas media reports, a three-year-old kitten named Venus has become popular on the Internet. Half of her face is pure black with green hair. Eyes, the other half is orange tabby stripes with blue eyes. How does a cat grow into this shape?
Two-faced Venus Cat
Many scholars called this strange kitten a chimera after research. In the legend, chimeras are special monsters created by combining the body parts of different animals. Feline chimeras are somatic cells in the body that contain two different DNA molecules, resulting from the mixing of two embryos. Among cats, chimeras are not particularly rare. Essentially, most male kittens are chimeras. If a kitten has a distinctly bright orange and black coat, it means it has an extra X chromosome. However, for female kittens, there are already two X chromosomes, so it is impossible for female kittens to have extra X chromosomes. This means that the kitten named Venus cannot be a chimera.
So, if you want to find out the reason, you need to use genetic methods. A cat has 19 pairs of chromosomes, one from the mother and one from the father. Genes are located on these chromosomes, and they provide the information necessary to produce a cat. All genes on all chromosomes make up the genome, a cat's complete genetic profile. Each gene has a specific location on the chromosome, so a gene may also be called a "locus." Therefore, each gene in a cat has a pair of alleles, one from the father and one from the mother. The genotype of each locus is determined by these two alleles. For example, aThe genotype of the long-hair locus of long-haired cats is "long (ll)", and this genotype is called homozygous.
Although the 19 pairs of chromosomes in the cat cell nucleus are identical, one pair of chromosomes is slightly different, which is the other chromosome that determines individuality. Females contain a pair of "X" chromosomes, represented by the symbol "XX", while males contain one "X" and one "Y" chromosome, so they are called "XY" chromosomes.
When a cat grows, two cells from different individuals - the egg and the sperm - combine together. Eggs and sperm are often called "germ cells". Unlike other cells in the body, the nucleus has only one set of chromosomes instead of two pairs of chromosomes. This means that when an animal is pregnant, the two groups combine to form a standard pair of chromosomes. The individual sex chromosomes of male sperm can be "X" or "Y", while the sex chromosomes of female eggs are all "X" type. Therefore, the gender of the kitten depends on whether the X sperm or the Y sperm is the first to interact with the egg. If it is a Y sperm, it will combine with the X chromosome of the egg to produce a male XY pair. After the egg and sperm unite, the two sets of chromosomes unite together in the nucleus of the fertilized egg.
Each type of reproductive cell has its own genes. The combined pairs of chromosomes contain the genes of sperm and eggs, but they are arranged into a "string of beads" of chromosomes in slightly different ways. It is these rearranged genes that make the fertilized egg and the resulting cat unique. The genotype of a short-haired cat can be deduced by examining the expression of the offspring obtained by mating it with a long-haired cat. Such a connection is called a test connection.
Different genes govern different traits
The color of a cat's hair, skin and eyes comes from Melanin. Melanin particles accumulate in the hair, and their shape, size and arrangement affect the color of the coat. There are two different types of melanin: true melanin and pheomelanin. It is generally believed that true melanin is spherical and absorbs almost all light and is therefore black; brown melanin is slightly elongated and rugby-shaped and can emit light in the red-orange-yellow range.
The appearance of most cats is almost unaffected by the environment. However, there is a particularly interesting variant: the Siamese allele (cs) at the albino locus causes a pigment expression barrier.Sensitive to temperature. The Siamese gene encodes a temperature-sensitive tyrosinase that is inactivated at the cat's core body temperature, causing the cat's body to appear light brown. However, this enzyme is active in limbs where the temperature is much lower, and it synthesizes a normal dose of pigment, which also gives Siamese cats their distinctive dark "tops." In fact, "indoor" Siamese cats that live in a cozy environment will often be lighter in color than their "outdoor" brethren, who can become quite dark in color during the cold winter months. The cb allele is also temperature-sensitive, but its effect is weaker than that of cs, so the facial expression is darker.
As for the cat named Venus mentioned above, there is a theory that all cells on one side of the cat’s face express melanin. The gene on the side is activated, while the other side expresses orange color. As the kitten continues to grow, these two areas of different coat colors converge at the midline of her body. This resulted in two halves of faces with different colors, but someone also discovered that this kitten had a special blue eye. Cat eyes often appear green or yellow, rather than blue. There is currently nothing geneticists can do about this problem, but I believe that with the development of science and technology, more genetic characteristics of cats will be revealed, and by then, answering these questions will not be so difficult.
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