Do all living organisms have chromosomes? Do all mammalian cells have these structures? How many chromosomes does this or that organism have? Genetics research such issues. Many similar questions have already been answered. Data on the number, size and shape of chromosomes are increasingly used in other biological sciences. In particular, in taxonomy.
Chromosomes are information structures
What is a chromosome? If we consider a eukaryotic cell under high magnification, then in the normal state of this "brick" of the body, we will not see any chromosome-like structures. They are formed only before cell division, and immediately after the end of reproduction, the dense structures disappear, as if dissolving. Chromosomes are necessary for the uniform distribution of informational material between daughter cells. They are formed by a DNA molecule and proteins that support the dense chromosome structure.
What is a karyotype
Each chromosome has its own size and shape. One type of organism is characterized by a specific set of chromosomes. Different individuals of the same species always have the same amount of data information structures, these structures have a size and shape characteristic of a particular species.
Thus, the karyotype is the external signs of chromosomes and their number in individuals of the same species. Unlike the genome, the karyotype does not include specific characters of individuals, but only the appearance of the chromosome structures. Signs of a karyotype help taxonomists to correctly distribute living organisms among taxonomic groups.
How many chromosomes in dogs
Each type of organism has a certain number of chromosomes. This applies to all eukaryotes. Prokaryotes have a ring DNA molecule, which also doubles during cell division and, without the formation of chromosomal structures, is distributed among daughter cells.
The number of chromosomes is extremely different in different representatives of the animal and plant kingdoms. For example, a person in somatic cells has 46 chromosomes. This is a diploid kit. There are 23 structures in human germ cells. How many chromosomes do dogs have? Their number cannot be simply guessed for each organism. A karyotype of a dog consists of 78 chromosomes. In this case, how many chromosomes does a wolf have? Here there is a similarity in karyotype. Because all wolves are relatives to each other and to the domestic dog. Almost all wolves also have 78 chromosomes in somatic cells. The exceptions are the red wolf and the bush dog.
How many chromosomes do dogs have in germ cells? In germ cells, there are always half as many chromosomes as in somatic cells. Because they are distributed equally between daughter cells during meiosis.
Apart from dogs and wolves, foxes belong to the canine family. There are 78 chromosomes in the karyotype of a dog. How many chromosomes do foxes have? Taxonomic genera of foxes are very heterogeneous in the number of chromosomes. The ordinary fox has 38. The sand fox has 40. The Bengal has 60.
How many chromosomes are there in a dog's red blood cells?
Red blood cells are red blood cells that serve as oxygen carriers. How are they arranged? Mature red blood cells must contain a large amount of hemoglobin. That is why they do not have many organoids, including chromosomes, since there is no nucleus at all.
However, there are in the blood of dogs, as well as in human blood, reticulocytes are immature red blood cells. They are only 1-2 percent of the total number of red blood cells. Reticulocytes contain ribosomal RNA, mitochondria, ribosomes, Golgi complex. But after a day or a day and a half, reticulocytes are transformed into mature red blood cells that do not contain DNA, and, consequently, chromosomal structures.
How many chromosomes are in the karyotype of other animals
Animal species are very diverse in karyotype. Moreover, the number of chromosomes in the nuclei of cells of various animals does not depend on the complexity of the organization of a living creature. So, for example, in the somatic cell of a frog 26 chromosomes. Chimpanzees have 48, which is slightly more than humans. Domestic chicken has 78 structures. This is as much as the chromosomes in dogs. The carp have 104, and the lamprey - the maxillary vertebrate - 174.
Chromosome Plant Set
The karyotype of plant forms is also extremely diverse. Soft wheat with a hexaploid set of chromosomes has 42 information structures, rye has 14, and corn has 20. Tomatoes have 24 chromosomes in each cell, the same for rice. Jerusalem artichoke has 102.
There are absolute record holders in the number of chromosomes in the plant kingdom. These are ferns.
In the cell of this ancient plant there are about 1200 chromosomes. Horsetail has many such structures: 216.
Thus, in all eukaryotic cells, except for red blood cells, there are chromosomes. Depending on the type of animal or plant, the quantitative composition of the chromosomes, as well as their size and shape, change. Precisely because chromosomes have different sizes, the number of these structures is so different. The smaller the structure, the more likely their number will be large.