Question

Which of the following are used to define the karyotype of the species?
1) The number of chromosomes.
2) The chromosome length
3) The positions of the centromeres

A) 1, 2 and 3 are correct
B) Only 1 and 2 are correct
C) Only 2 and 3 are correct
D) Only 1 and 3 are correct

Answer 1

Hint:Karyotyping is a technique used to define the karyo components (chromosomes), chromosomes are characterized based on their length, size, appearance, position of centromere and type of chromosomes.

Complete answer:
Karyotype is derived from grrek word kernel means components of nucleus, it is basically an arrangement of chromosomes which is based the above features mentioned in the hint, arrangement of chromosomes is based on the decreasing order of their size. Karyotype is the appearance of the homologous chromosomes within a cell which is represented by an ideogram. Karyotyping is necessary to identify the abnormalities in chromosomal structure.Karyotyping is of two types symmetrical karyotyping and asymmetrical karyotyping. Symmetrical karyotyping, it is the most primitive method, will have chromosomes which are approximately of same size and will have median centromere. The other form is Asymmetrical type which will have chromosomes of different lengths and position of centromere, it is the recent method of karyotyping which is used in animals with higher chromosome number.
Therefore, the correct answer is Option ‘A’.

Note:Ideogram is the diagrammatic representation of karyotyped chromosomes representing its morphological features of the chromosomes, this will distinguish each arm of a chromosome and differentiates them into long and short arms. These techniques change information about the abnormalities in the chromosomes.