Difference Between Somatic Cells and Gametes

Main Difference – Somatic Cells vs Gametes

Somatic cells and gametes are two types of cells which are involved in asexual and sexual reproduction of organisms, respectively. Somatic cells can be found everywhere in the body whereas gametes are restricted to reproductive organs. Male gametes are called as sperms while female gametes are called as ova. The main difference between somatic cells and gametes is that somatic cells consist of diploid a genome whereas gametes consist of a haploid genome.

This article looks at,

1. What are Somatic Cells
      – Definition, Production, Characteristics, Function
2. What are Gametes
      – Definition, Production, Characteristics, Function
3. What is the difference between Somatic Cells and Gametes

What are Somatic Cells

Somatic cells are any type of a biological cell, typically the regular type of body cells other than the reproductive cells.  That means, somatic cells are only involved in the asexual reproduction. Somatic cells are diploid in humans, containing two sets of homologous chromosomes. During asexual reproduction, somatic cells are produced by mitosis, creating identical two copies of new cells from a single mother cell. However, some species contain haploid somatic cells. Haploid somatic cells can be found in species, which develop alterations of generations.

Somatic cells are originated from stem cells. The stem cells in the zygote are differentiated into distinct types of somatic cells, which are capable of creating structures like organs in multicellular organisms. The differentiation of stem cells into a particular somatic cell type in the body depends on the time of differentiation and environmental factors. Functions of the differentiated somatic cells can be completely different from each other. An adult human body may contain around three trillion of somatic cells in the body. They are differentiated into form neuron cells, blood cells, muscle cells, liver cells, etc. Neurons come together to form the nervous system. Blood cells are a part of the cardiovascular system. Cells like liver cells and stomach cells are involved in the formation of the digestive system. Red blood cells in the cardiovascular system are shown in figure 1.

Figure 1: Red blood cells

Somatic cell mutations can occur during replication. However, these mutations in somatic cells have no contribution to the evolution, since they have no way to pass them to the offspring.

What are Gametes

Gametes are either mature male or female germ cells, which are capable of fusing with other germ cells to form the opposite sex, forming a zygote. In eukaryotes, all multicellular organisms undergo sexual reproduction by producing gametes, in order to create offspring. Gametes are restricted to reproductive organs of the multicellular organisms. They usually contain a single set of chromosomes and are called haploid. During sexual reproduction, gametes are produced by meiosis of germ cells located in gonads. Gametes are morphologically distinct depending on the sex. In humans, male gametes are known as sperms and female gametes are known as ova. Since gametes are haploid, the fusion of two gametes of opposite sexes would regenerate the diploid zygote. Therefore, half of the total DNA is contributed by each parent to the offspring. After fertilization, the zygote contains two sets of homologous chromosomes, each set coming from one parent. The ovum and sperms in humans are shown in figure 2.

Figure 2: The human ova and sperms

Mutations in gametes can also occur during replication. They can be insertions, deletions of nucleotides in DNA or even chromosomal aberrations. These mutations are carried out to the offspring through gametes. Then, the offspring may contain variations in alleles compared to their parents. The most favorable characters will be selected by natural selection.

Difference Between Somatic Cells and Gametes

Definition

Somatic Cells: Somatic cells are any form of a biological cell, other than a reproductive cell.

Gametes: Gametes are either mature male or female germ cells, which are capable of fusing with another germ cells of the opposing sex, forming a zygote.

Ploidy

Somatic Cells: Somatic cells contain diploid genome.

Gametes: Gametes contain a haploid genome.

Homologous Pairs

Somatic Cells: Somatic cells contain homologous chromosome pairs.

Gametes: Gametes contain individual chromosomes.

Reproduction

Somatic Cells: Somatic cells are involved in asexual reproduction.

Gametes: Gametes are involved in sexual reproduction.

Male and Female Cells

Somatic Cells: Somatic cells are same in both sexes.

Gametes: Gametes are different in two sexes; male gametes are called as sperms and female gametes are called as ova.

Production

Somatic Cells: Somatic cells are produced during asexual reproduction by mitosis.

Gametes: Gametes are produced during sexual reproduction by meiosis.

Number of Daughter Cells per One Cell Division Cycle

Somatic Cells: Two identical daughter cells are produced from a single stem cell.

Gametes: Four daughter cells are produced from a single germ cell.

Differentiation

Somatic Cells: The cells produced by mitosis are differentiated into distinct types of somatic cells, which are specialized for a certain function.

Gametes: The cells produced by meiosis of germ cells are directly used as gametes.

Formation of Structures

Somatic Cells: Somatic cells are involved in the formation of structures in the body like organs.

Gametes: Gametes are not involved in the formation of structures.

Found in

Somatic Cells: Somatic cells can be found everywhere in the body.

Gametes: Gametes are restricted only to reproductive organs.

Fusion during Reproduction

Somatic Cells: Somatic cells are not fused with the other somatic cells during reproduction.

Gametes: Gametes are fused with other gametes of the opposite sex during reproduction.

Origin

Somatic Cells: Somatic cells are originated from stem cells.

Gametes: Gametes are originated from germ cells.

Mutations

Somatic Cells: Mutations in the somatic cells are not carried to the offspring. Therefore, they have no effect on evolution.

Gametes: Mutations of gametes are carried to their offspring. Therefore, they contribute to the evolution.

Examples

Somatic Cells: Examples for somatic cells are muscle cells, nerve cells and the cells in the blood stream etc.

Gametes: Sperms and ova are the examples for the gametes.

Conclusion

Somatic cells and gametes are the two types of cells in the body of a multicellular organism. Somatic cells are found everywhere in the body, differentiating into a variety of cell types in order to carry out distinct functions. They also form structures like organs in multicellular organisms. Gametes are restricted to reproductive organs. They are involved in the fusion with other gametes during fertilization in order to form the zygote. Somatic cells are produced by mitosis and gametes are produced by meiosis. Therefore, somatic cells are diploid, containing two homologous chromosome sets but gametes are haploid, containing a single set of chromosomes. Fertilization of gametes regenerates the diploid structure of the somatic cells. Mutations in gametes are carried out to the offspring, creating different variations of alleles in the offspring. The main difference between somatic cells and gametes is mainly in their ploidy.

Reference:
1. Scoville, Heather. “What is the Difference Between Somatic Cells and Gametes?” ThoughtCo. N.p., n.d. Web. 24 Mar. 2017.
2. Alberts, Bruce. “Fertilization.” Molecular Biology of the Cell. 4th edition. U.S. National Library of Medicine, 01 Jan. 1970. Web. 24 Mar. 2017.
3.Griffiths, Anthony JF. “Somatic versus germinal mutation.” An Introduction to Genetic Analysis. 7th edition. U.S. National Library of Medicine, 01 Jan. 1970. Web. 24 Mar. 2017.

Image Courtesy:
1.”75302″ (Public Domain) via Pixabay
2. “956482” (CC0) via Max Pixel

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