Chromosomes are coiled structures containing the genetic material DNA. The chromosome number of organisms is constant per species. And while you cannot identify a species depending on the chromosome number alone, the knowledge about it can help you learn more about that organism.
Genetic studies show that jackals, dingoes, coyotes, and almost of all wolf species have the same number of chromosomes as dogs. That means that technically all these aforementioned species can interbreed.
With almost 400 genetically different breeds of canines, the domestic dog can be considered as one of the most diverse terrestrial animal (in terms of physical appearance) on Earth.
But in terms genes, how diverse are they? How many chromosomes do these furry friends have? Let’s explore them in detail below.
Short Answer: Dogs have a sum of 78 chromosomes (2n).
Dog Chromosome Number
Chromosome number in living organisms, be it plants, animals, or even microorganisms, serve as the primary basis of hybridization since the number remains almost constant within species. Hence, this fact becomes an important factor regarding organism breeding.
- Dogs, which are under the species Canis lupus familiaris, are known to have a total of 78 chromosomes (2n). The diploid genes can be classified into 38 pairs with two sex chromosomes. On the other hand, the haploid genome is about 2445 Mb.
- Aside from being our loyal pets, they can serve as model organisms for scientific studies because of their genetic diversity.
- Dogs are particularly known to practice inbreeding and hence are highly susceptible to genetic diseases and disorders like cancer, blindness, deafness, and even autoimmune diseases. Take a closer look at the reference genomes of dogs in this link.
Structure of The Dog Chromosomes
The aforementioned diploid chromosome number was found to be in both male and female dogs. Just like in humans, dogs have two sex chromosomes, the X, and Y. The sex cells of females consist of two X chromosomes while male sex cells consist of an X chromosome and a Y chromosome.
- Regarding structure, the autosomes, or the chromosomes found in the somatic cells, contain centromeres that are located terminally or almost.
- While the information about the nature of the chromosome arms is still unclear, a study by Japanese scientists revealed that the largest chromosome pair in dogs could be regarded as the largest among the autosomes.
- And just like in humans, the X chromosome of dogs is one of the largest, whereas its complement, one of the smallest.
Importance of Chromosome Number in Dogs
The knowledge about the chromosome number of animals is important to facilitate the successful crosses between them. As mentioned earlier, it can serve as the basis for hybridization under same species, which are often done in dogs to create the so-called “pure-breed” or “hybrid“.
- But again, it is good to note that the chromosome number alone does not determine such capability.
- Other factors such as chromosome shape and size, as well as the presence of lethal genes, should also be considered.
At present, there is relatively little information to be found in the literature about the genetic makeup of dogs.
But who knows if scientists may discover something significant about these loyal pets’ genome in the future?
- “Chromosome Number in Some Crops and Animals”. Accessed December 12, 2017. Link.
- “Welcome to the Living World: Chromosome Number of various Animals”. Accessed December 12, 2017. Link.
- “Canis lupus familiaris (ID 85) – Genome – NCBI”. Accessed December 12, 2017. Link.
- “THE CHROMOSOMES OF THE DOG – GUSTAVSSON – 2009 – Hereditas – Wiley Online Library”. Accessed December 12, 2017. Link.
Answer
Hint: Chromosomes are present inside the nucleus. It is like a thread. Present in both plant and animal cells. Chromosomes have protein. In fact it is made up of protein and a one deoxyribonucleic acid (DNA) which transfers from parent to its duplication. DNA has a special character and it has self-replication quality.
Complete answer:
• Dogs have 78 Chromosomes in their diploid cells. In simply diploid cells (2n) means two sets of chromosomes are there in the cell. Haploid (n) cells mean only one cell is present. • In Dogs, $\dfrac{{2n}}{n} = \dfrac{{78}}{2} = 39$ Haploid chromosomes are present in dogs.• In details, at the time of meiosis, in the equator line \[78\] chromosomes present at the equator of the cells in this region the chromosomes are already replicated. • The haploid cells contain \[39\] chromosomes. • There is a difference between Anaphase in Mitosis and Meiosis I. • Here centromere will not divide, so the sister chromatids are present together without splitting.Hence \[39\] chromosomes are present at the poles of the cells.
Then the number of chromosomes is decreased by \[2n\] to \[n\]. Then the cells undergo Meiosis II provide the 4 haploid daughter cells with exactly half of the chromosome number of the parent cell.Note: Diploid cells have two sets of chromosomes. The deviation is in the cells in the gremlin. This generates gametes or sperm.
Haploid means it has only one set of chromosomes. In human \[23\] chromosomes are present. \[23\]Diploid \[\left( {2n} \right)\] cells and \[12\left( n \right)\] haploid cells are present in the human body. Mainly chromosomes are of four types : Metacentric, Acrocentric, Telocentric, Sub metacentric chromosomes. Linear chromosomes are present in eukaryotes.