Are mules divided into male and female?

Mule is a hybrid of horse and donkey, and the genes of male donkey and mare are easier to combine, so most mules cross in this way. the chance of gene combination between male horse and female donkey is very small. some horses take six years to successfully mate and make donkeys pregnant. Many friends can't help but ask, which mule divides male and female? Let's take a look at it together.

Are mules divided into male and female?

Mules are divided into male and female. Mules can be divided into male and female, but male mules and most female mules are sterile because chromosomes are not paired (63), germ cells cannot divide normally (meiosis), female mules have sexual function, and the uterus can conceive embryos, but the most difficult thing is to get female mules pregnant. Strictly speaking, the offspring of male donkeys and mares are called horse mules, and the offspring of male and female donkeys are called donkey mules.

The difference between a mule and a horse

1. Ma Sheng's horse mule is bigger than donkey mule, but both horse mule and donkey mule are smaller than horse and bigger than donkey.

2. Horse mules and donkey mules have a short length of hair at the base of their tails, while the horse roots all have very long hair.

Mules have longer and wider ears than horses.

4. There are 32 pairs of chromosomes in horses, 31 pairs of donkeys and 31.5 pairs of mules, one of which is not paired, so they are generally infertile.

Why can't mules have children?

1. Both horse mule and donkey mule have abnormal chromosome numbers, because donkey chromosome 2 is homologous to horse chromosome 1, donkey 13 and horse 11, donkey 14 and horse 13. Donkey 16 and donkey 25 add up to horse 5, and horses have 32 pairs of chromosomes, while donkeys have 31 pairs. Although horses and donkeys are closely related, their gametes can not only combine with each other, but also develop into complete individuals, but the number of chromosomes in their offspring is 32-31, no matter how one chromosome is lonely.

2. But the mule is still lucky, because if this is the number of chromosomes in the cell of a horse (if it is a horse, it is called a monosomic 2n-1), then it basically cannot survive. For diploid species that reproduce sexually, pure haploids are better than this state. On the other hand, if it is the composition of chromosomes in a donkey cell, it becomes trisomy, and the extra chromosome must have three. 32-31 mules are not really 31-to-1 relationships. In other words, during meiosis, it does not simply separate 31 pairs of chromosomes from each other, and then randomly assign the extra one. This is the trouble encountered by mules and even other hybrid animals, whose chromosomes tend to be randomly separated and combined freely in the process of separation. Because for the surviving trisomy, although its fertility is lower than normal, it is also quite high, with the exception of that extra chromosome, the rest can be paired normally and separated from each other.

3. For an unfortunate mule (take the female mule as an example), what is the chance of producing a normal egg, for example, in an extreme case, the egg happens to contain 31 chromosomes from a donkey or 32 chromosomes from a horse. Obviously, this probability is quite low (interested comrades can calculate it), of course, the actual situation does not need to be so extreme, after all, the mule itself can survive, that is to say, it can be a harmonious combination of horse and donkey chromosomes in the egg.