5+ Types of Chromosome: Detailed Explanations

Chromosomes are the structures that are seen in the center of the cells being the nucleus and carries long parts of the DNA.

Chromosomes on the basis of its length can be classifies into four considering the position of the centromere. The types of chromosomes based on it and others are-

In any type of organism found, the classification of the chromosomes can be recognized by its size, its number, position, the way it binds and its centromere. In the karyotype of the human or the chromosome of the body that includes the non-sex cones are mostly organized in the approx. size order from large to the smallest one. DNA is the material that holds genes. It is the building block of the human body.

In the humans, each of the cells is normal and has 23 pairs of the chromosomes and is a total of 46 in number. Among this twenty two of them are called the autosomes and it is the one that looks similar in both female and males. The 23rd one is called the sex chromosome. Each of the chromosomes is made of DNA coiled up tight.

Chromosomes are the basic blocks that build a life and that carries all the data needed to help get a cell grow, struggle and stay along with getting reproduced. The chromosomes are made up of the DNA. The molecule of DNA is paced into thread like ways called the chromosomes. The coiling up is done several time and is called histones.

The types of chromosomes always are seen in pair. In general, each of the human body cell has a pairing of 23 chromosomes. One half comes from the father and the other half is taken from the mother. Two of the chromosomes get to decide the sex of the born child with female having 2X chromosomes and males having one X and one Y of them. Chromosomes also contain proteins that help DNA exist in the proper form.

types of chromosome
Image credit-ChromosomeWikipedia

Autosomes

It is not the sex chromosomes. The member in this type is a diploid type and is 22 in pair.

Despite it being a diploid cell it has the similar morphology unlike the allosome pairing that have separate structure. Among the types of chromosome they are the 22 pairs in number. The DNA is called auDNA.

All of the humans have genome being diploid that have 22 pairs of the autosomes and one of the allosome. The pairing of the autosomes is done in number depending on the size while the allosome is done with letter. Allosome pairs have two of them being X and Y.

There are disorders related to the autosomes and are called the autosomal genetic disorder and can take place for any number of reasons. Some of them are most basic being the non-disjunction in the germ cell while Medellin inheritance can also be one of them. The disorder of it can be recessive type.

All of the autosomes in the human can be identified by getting the chromosomes extracted from the cell and arrest them while during the metaphase after staining it with a dye type. These chromosomes are called to be karyograms with making it easy to compare. It is also responsible for a type called the Patau syndrome having three copies of chromosome 13.

The autosomal recessive disorders need two copies if the allele for the manifesting of the disease. At is possible to have one copy if the defect allele without having any phenotype of the disease two normal parent can have a child with the disease if both of them seen to carry for the same way.

Image credit-AutosomesWikipedia

Sex chromosome

There are a total of 46 chromosomes in number which comes in pairing of 23. Out of this, the 23rd pairing is the sex chromosome.

There are the two types of chromosomes mainly called the autosomes and the sex chromosomes. The one that checks upon the sex of the unborn child being it male or female is called the sex chromosome. The females have two X and the males have one of each X and Y.

The mother is seen to give X chromosome to the child while the father contributes to wither giving it Y or X. the chromosomes that are given by the father determines the sex of the baby being born. The rest of the chromosome is the autosomal ones. It helps in sex determination.

All the mammals and humans have two of the sex chromosomes being X and Y. Male have both and females have only X. The egg cells have all the X chromosome while the sperm cells have both X and Y. This arrangement clearly states that the sex of the child is determined by the male after fertilization.

In other mammals, if it same as that of the humans but can differ on the names. There is a good discrepancy in the size of these two types of chromosomes with X being larger than Y. They do also have different types of genes in them carried forward. It is the actual combination type that determines the sex of the child.

The sex chromosomes are actually interesting. This is not cause for the fact that they have a role or important but for the fact that they are different from the rest of the chromosomes present that complete the human genome system. All the sex li ked disorder is often carried by the X chromosome.

Image Credit-Sex chromosomeWikipedia

Acrocentric chromosome

In the humans, the chromosome with the number 13, 14, 15, 21 and 22 are said to be acrocentric and is linked with Robertsonian transaction.

These types of chromosomes are same in cytogenetocally the shorter arm that is very poor in its gene type. The vital contribution of the cell is that the shorter arm is acrocentric and carries the organized area having nucleolus in p12.

There in total of six acrocentric chromosomes in the human system of genomic. It is the type where the chromosome is located in the close area where one is places in the end of the terminal and is thus called the acrocentric chromosome. Here one arm is long and other is short. At the time of cell division in the phase of anaphase, they take up the shape of J.

The Robertsonian Translocation takes place between two of the acrocentric chromosome that have its centromere at the close end of the chromosome and results in the smaller length of the gene area way belong the centromere. Number 13, 14, 15, 21, 22 and the Y chromosome are classified under this. It occurs for the outcome of the gen compliment of the 45 chromosome.

Chromosomes are the fundamental making blocks of life, including all of the information required to make a cell grow, struggle, and again produce. DNA is what makes up the chromosomes. The DNA molecule is strung together in thread-like patterns called chromosomes. Histones are the coiling up that is done multiple times.

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HistonesWikipedia

The classification of chromosomes may be recognised in any type of organism by their size, number, position, binding pattern, and centromere. The non-sex cones are typically ordered in the karyotype of the human, or the chromosome of the body, in approximate size order from large to smallest.

Sub metacentric chromosome

It is the part that has its centromere seen in the middle with having unequal length of arms.

Any type of chromosome that has its arm length not so equal to a bit as well and can make a shape of L is called Sub metacentric chromosome. It has a dense centromere in the defined area of the chromosome.

It includes with it sequel of DNA that repeats and is thus highly efficient packed in the heterochromatin. The centromere serves to be the site of the kinetochore area and thus is vital for getting it aligned to the chromosomes at the time of cell division. It is a site of kinetochores gathering. It is vital for its alignment in metaphase.

The presence of these chromosome outcomes in the feature seen in its chromosomal arms. The arm is quite effective and is small called the p while the one that is long is called to be the q. Based on the place of the centromere, the chromosome can be classified into the types. It has a middle located centromere.

With having the centromere in the middle it has two different levels of arms being p and q. The number of chromosome marked as 2, 4, 5, 6, 7,8,9,10,11,12,17,18 and the X chromosomes are said to be sub metacentric. Chromosome 2 is said to be the largest.

In the human genomic system, there are a total of six acrocentric chromosomes. The acrocentric chromosome is the type in which the chromosome is located in the close area where one is placed at the end of the terminal. One arm is long, while the other is short. There are about 242 billion pairs of chromosome 2.

Telocentric chromosome

The centromere of a telocentric chromosome is positioned at one end of the chromosome for which the p arms are not seen.

The centromere is so close to the chromosome’s end that the p arms aren’t visible, or are barely visible. Subtelocentric chromosomes have centromeres that are closer to the end than the center. The centromere is so close to the end of the chromosome that the p arms are obscured or barely visible.

Unpaired chromosomes occasionally misdivide during meiosis, breaking at or near the centromere to produce either telocentric chromosomes or isochromosomes. Most, but not all, monotelosomic potentially number 42 and ditelosomic wheat plants are normal and fertile enough to be kept as separate genetic stocks. As telocentric chromosomes can be identified cytologically, they have special uses in gene localization to chromosome arms.

Also for this in checking the identities of monosomic chromosomes by testcrossing, and for within chromosome recombination and mapping. Telocentric mapping exploits the use of the telosomes as a centromere marker. The centromere serves as the site for kinetochore assembly and therefore it is essential during the alignment of the chromosomes at the metaphase plate and the subsequent segregation of chromosomes during cellular division.

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Kinetochore assemblyWikipedia

The presence of the centromere results in the characterization of the chromosomal arms. The arm that is relatively shorter is called p whereas the one that is longer is called q. Based on the position of the centromere, the chromosome may be described as metacentric, submetacentric, acrocentric, telocentric, subtelocentric, and holocentric. Both telocentric and subtelocentric chromosomes have not been observed in humans.

Metacentric chromosome

A metacentric chromosome is one with a centrally located centromere. As a result, the lengths of the chromosomal arms that are the p and q arms are nearly equal.

In humans, chromosomes that are metacentric include chromosome 1, chromosome 3, chromosome 16, chromosome 19, and chromosome 20. Each chromosome has a single centromere. Its location on the chromosome can change. Normal chromosomes each have a single centromere.

The centromere of a metacentric chromosome is located halfway between the ends of the chromosome, separating the two arms of the chromosome. Submetacentric chromosomes have centromeres that are visibly off-center. Centromeres on acrocentric and telocentric chromosomes are located very close to and at the end of the chromosome, respectively.

The centromere is located at the end of the chromosome, adjacent to the telomere, in the case of telocentrics. During metaphase in many organisms, when chromosomes are at their most condensed, the centromere can be seen as a constriction where the replicated chromosome’s chromatids are held together. The metacentric chromosomes appear to be V-shaped. A metacentric chromosome can also have the shape of an X.

Metacentric chromosomes are X-shaped chromosomes with the centromere in the center, allowing the two arms to be equal. These chromosomes appear V-shaped during anaphase because the chromosomes split and the daughter chromatids move to opposite poles of the cell. As a result, the correct answer is ‘V-shaped.’ Metacentric chromosomes have the centromere located midway between the ends of the chromosome, separating the two arms of the chromosome 

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