Types of Chromosome on the Bases of Centromere

Types of Chromosome on the Bases of Centromere
There are four types of chromosome according to the position of centromere are as follows.
i. Telocentric Chromosome
ii. Acrocentric Chromosome
iii. Sub-Metacentric Chromosome
iv. Metacentric Chromosome
i. Telocentric Chromosome
When the centromere is placed at the extreme end of the chromsome, the chromosome is called Telocentric Chromosome.
ii. Acrocentric Chromosome
When the centromere is placed near the end of the chromosome, the chromosome is called Acrocentric Chromosome.
iii. Sub-Metacentric Chromosome
Chromosome with unequal arms (chromatids) that resembling the “j” shape are called Sub-meta Centric chromosome.
iv. Meta Centric Chromosome
Chromosome with equal arms and centromere in center is called a Metacentric Chromosome.
There are three more types of chromosomes
i. Homologous Chromosome
ii. Autosomes
iii. Sex Chromosomes
i. Homologous Chromosomes
Those chromosomes which are morphologically similar with same set of genes in which one chromosome comes from male and another from female is called as Homologous Chromosome.
ii. Autosomes
The somatic paired chromosome which contain the genes of various characters except reproductive organs are called Autosomes.
These are same in male and female both.
iii. Sex Chromosome
Those chromosomes in a cell by which the sex of organism can be determined are called Sex-Chromosome.
There are different types of distribution of Sex-Chromosome.
i. XY type distribution
ii. ZW type distribution
i. XY Type Distribution
Females have a pair of similar sex chromosomes called X but males have a mismatch set and X and another chromosome called a Y, so the male XY and the female is XX.
ii. ZW Type Distribution
In some fishes, moths and birds, the male have similar chromosome called Z and the female has different so the male is ZZ and the female is ZW.
Chromosomes as Carrier of Genes
Genes are small bodies found in the chromosomes.
Chromosomes are considered as the carrier of genes.

• The chromosomes can be separately identified visually but the genes are very small units. And so far have not been seen even with the best microscope.
• The chromosomes and gene behave as hereditary units but the genes can not be considered outside the chromosome.
• At the time meiosis, the separation of homologous chromosomes takes place which result in the segregation of gene pairs.
• In the genotype of every individual one member of each pair of genes is contributed by one parent and the other by the other parent.