Difference Between Metacentric and Submetacentric Chromosomes

Key Difference – Metacentricvs Submetacentric Chromosomes

The organized cellular structure in which theDeoxyribose Nucleic Acid (DNA)molecules are tightly packaged is known as aChromosome. Chromosomes reside in thenucleusand contain all thegenesthat are responsible for the production ofproteinsrequired for different functional aspects of the cell. The total number of chromosomes in organisms differs according to the species. In humans, there are 23 pairs of chromosomes accounting a total of 46 chromosomes. These 23 pairs are composed of 22autosomal chromosomepairs and onesex chromosomepair. Chromosomes can be categorized based on different criteria taking different aspects into consideration. Based on the position of thecentromere, chromosomes are categorized into four groups; Metacentric Chromosomes, Submetacentric Chromosomes,Acrocentric chromosomesandTelocentric chromosomes. In metacentric chromosomes, the centromere is located in the exact middle of the chromosomes giving rise to two equal length arms. Submetacentric chromosomes are the chromosomes in which the centromere is located a little away from the midpoint, thus resulting in unequal length arms. In humans, most chromosomes belong to this type. Thekey differencebetween the Metacentric and Sub-metacentric chromosomes is based on the positioning of the centromere in the chromosome.In Metacentric chromosomes, the centromere is located right at the midpoint of the chromosome, whereas in Submetacentric chromosomes, the centromere is located a little away from the midpoint.

CONTENTS

1.Overview and Key Difference
2.What are Metacentric Chromosomes
3.What are Submetacentric Chromosomes
4.Similarities Between Metacentric and Submetacentric Chromosomes
5.Side by Side Comparison – Metacentric vs Submetacentric Chromosomes in Tabular Form
6.Summary

What are Metacentric Chromosomes?

Metacentric chromosomes are the chromosomes in which the centromere is located in the middle position of the chromosome. The centromere is composed of a DNA region, and it is the structure which holds the twosister chromatidstogether in place. In addition, the centromere is involved in the spindle formation process during thecell division. The centromere binds to thekinetochoreproteins to form the spindle apparatus during bothmitosis and meiosis.

Owing to the structure of the metacentric chromosomes, they are composed of two equal-sized arms, and in the cell division phase, they appear as ‘v’ shaped structures during themetaphaseof the cell division. The presence of metacentric chromosomes is mostly observed in primitive organisms.KaryotypingusingGiemsa staininghas enabled thecytogeneticsto characterize these chromosomes. The karyotyping done on primitive organisms to observe metacentric chromosomes is referred to as ‘symmetric karyotype’. The human chromosomes 1 and 3 belong to this type and amphibians are composed mainly of metacentric chromosomes.

What are Submetacentric Chromosomes?

In Submetacentric chromosomes, the centromere is located slightly away from the midpoint of the chromosome. Therefore, this positioning of the centromere results in unequal sized arms of the chromosome. In usual structure analysis after karyotyping, the submetacentric chromosomes appear to have shorter p arms and longer q arms.

During the mitosis and meiosis phases, the submetacentric chromosomes assume an ‘L’ shaped structure in the metaphase stage. When the metaphase chromosomes are observed under the microscope, this type of chromosome can be distinguished easily from the others. Most of the human chromosomes belong to this type.

What are the Similarities Between Metacentric and Submetacentric Chromosomes?

• Both Metacentric and Submetacentric Chromosomes types are composed of highly compact DNA.
• Both Metacentric and Submetacentric Chromosomes structures are categorized based on the position of the centromere.
• Both Metacentric and Submetacentric chromosomal types are present in humans.
• Both Metacentric and Submetacentric Chromosomes structures can be identified by karyotyping using Giemsa
• Both Metacentric and Submetacentric Chromosomes structures can be subjected to different chromosomal aberrations or mutations leading to different health complications.

我s the Difference Between Metacentric and Submetacentric Chromosomes?

Metacentric vs Submetacentric Chromosomes
In Metacentric chromosomes, the centromere is placed in the exact middle point of the chromosomes giving rise to two equal length arms.	Submetacentric chromosomes are the chromosomes in which the centromere is placed a little away from the midpoint, thus resulting in unequal length arms.
Structure Formed During Metaphase of Cell Division
Metacentric chromosomes appear as V-shaped in metaphase.	Submetacentric chromosomes appear as L shaped in metaphase.
p and q arms
Metacentric chromosomes have equal sized p and q arms.	Submetacentric chromosomes have shorter p arm and comparatively lengthier q arm.

Summary – Metacentricvs Submetacentric Chromosomes

染色体是高度紧凑的DNA结构are responsible for housing the genes. Based on the positioning of the centromere, chromosomes are categorized as metacentric, submetacentric, acrocentric and telocentric chromosomes. Metacentric chromosomes are the ones having the centromere placed in the middle of the chromosome. Therefore, this results in equal sized p and q arms. Submetacentric chromosomes are the chromosomes in which the centromere is placed slightly away from the centre. Thus, this type of chromosomes is composed of a short p arm and a longer q arm. Both types are found in humans, and they can be observed via karyotyping. This is the difference between metacentric and submetacentric chromosomes.

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Reference:

1.“Easy Biology Class.” Easybiologyclass.Available here
2.“Types of Chromosomes.” BiologyWise, biologywise.com/types-of-chromosomes.Available here

Image Courtesy:

1.’156403′ by OpenClipart-Vectors (Public Domain) viaPixabay
2.’Centromere Placement’By Fockey003 – Own work,(CC BY-SA 4.0)viaCommons Wikimedia