Similarities Between Oogenesis and Spermatogenesis

Gametogenesis is a process of formation of highly specialized haploid gametes in animal organisms and humans. The process takes place in the gonads through meiosis. In male organisms, the process is called spermatogenesis, in female organisms it is called oogenesis.

What is Oogenesis?

The process of formation of female gametes is called oogenesis. It uses oocytes generated before birth. With aging, there is a continual decrease of the oocytes’ numbers.

Oogenesis takes place in the ovaries, in three consecutive phases:

Multiplication:

The multiplication begins with a series of mitotic divisions of primordial germ cells. A large number of diploid oogonia are formed. In female mammals, this phase ends before their birth. The cells are retained in the ovaries, until the maturity of individuals is reached. Then they proceed to the growth stage.

Growth:

Through the growth phase, the oocytes increase their size. This phase is much more significant in the oogenesis that in the spermatogenesis. Upon growth, the oocytes accumulate nutrient reserves, needed to feed the future embryo.

Maturation:

During the maturation phase, the most important process is the meiotic division. Mature haploid gametes are obtained from immature diploid cells. After the first meiotic division, two cells with different size are formed – one large cell (secondary oocyte) and one small cell (polar body). After the second meiotic division, one mature egg and three polar bodies are formed.

What is Spermatogenesis?

The process of formation of male gametes is called oogenesis. It is a continuous production process. Sperm cells are constantly being produced from puberty to old age.

Spermatogenesis takes place in the testes. It runs in four consecutive phases:

Multiplication:

The multiplication phase begins with series of mitotic divisions of primordial germ cells. A large number of immature sex cells (spermatogonia) are formed that retain their diploid chromosomal set. The multiplication phase in spermatogenesis is longer and more intense than in oogenesis.

Growth: 

In the growth phase, the primary spermatocytes increase their size.

Maturation: 

At the maturation phase, the meiotic division takes place. Mature haploid gametes are formed. After the first meiotic division, 4 identical cells are obtained – secondary spermatocytes. After the second meiotic division, 4 identical spermatides are formed.

Spermiogenesis:

In the spermatogenesis, there is a forth phase, absent in the oogenesis – spermiogenesis. During this phase, the immature gametes develop to sperms. The result is four mature, small, and motile spermatozoids.

What are the Similarities Between Oogenesis and Spermatogenesis

Similarities in Terms of “Definition”

Both oogenesis and spermatogenesis are processes of formation of highly specialized haploid gametes in animal organisms and humans. They both take place in the gonads through meiosis.

Similarities in Terms of “Phases”

Oogenesis and spermatogenesis run in essentially the same way in three consecutive phases: multiplication, growth, and maturation.

Similarities in Terms of “Cells”

In both processes, mature haploid gametes are obtained from immature diploid cells through meiosis.

Similarities in Terms of “Importance”

As a result of the formation of haploid gametes during the spermatogenesis and oogenesis, the chromosomes are recombined in the formed gametes. This increases the genetic variability of the offspring.

The gametogenesis provides for the generation of a diploid chromosome set after the fertilization.

Summary:

• The process of formation of highly specialized haploid gametes in animal organisms and humans is called gametogenesis. It takes place in the gonads through meiosis. In male organisms, the process is called spermatogenesis, and in female organisms, it is called oogenesis.
• The oogenesis uses oocytes generated before birth. With aging, there is a continual decrease of the oocytes’ numbers. Oogenesis takes place in the ovaries, in three consecutive phases: multiplication, growth, and maturation.
• The spermatogenesis is a continuous production process. Sperm cells are constantly being produced from puberty to old age. Spermatogenesis takes place in the testes. It runs in four consecutive phases: multiplication, growth, maturation, and spermiogenesis.
• In both processes, mature haploid gametes are obtained from immature diploid cells through meiosis.
• In both processes, the chromosomes are recombined in the formed cells. This increases the genetic variability of the offspring. The gametogenesis provides for the generation of a diploid chromosome set after the fertilization.