homologous chromosomes in humans

In the diploid number, chromosomes are always found in pairs. In each pair there are two identical chromosomes, called homologous chromosomes. These chromosomes are identical in size, appearance and position of the centromere. Apart from this, the t..

As can be seen from the human karyogram, the chromosomes are classified into two types, autosomes and sex chromosomes. The autosomes have homologous chromosomes as pairs whereas the sex chromosomes are of two different types - X and Y. A f..

>Culturing of human cells invitro, help in understanding the biochemical basis of inheritance. Human cytology and karyotyping helps in ascertaining the number, shape size and structural features of chromosomes. Study of monogygotic twins helps in distinguishing between..

They are mutation involving change in number or structure of chromosomes. Change in number of chromosomes induced by mutagens can lead to aberrant gametes, which when fuse with normal gamete lead to aneuploid zygotes. Changes in chromosomal structure by mutation are b..

. Such a chromosome assumes the shape of 'V' during anaphase. Sub-metacentric, where the centromere is slightly away from the centre and hence the two arms are unequal. Such a chromosome attains the shape of 'L' during anaphase. Acrocentric, where the centromere is situated far ..

With the rediscovery of Mendelism, several scientists focussed on identifying the basis for inheritance. William Sutton recognised a close parallelism between the transmission of 'factors' identified by Mendel and the behaviour of chromosomes during meiosis and fertilization. These ideas ..

These chromosomes occur in the oocytes (germcells in the ovary) of amphibians and in some insects. They are extremely large synapsed homologous chromosomes which can be seen in the diplotene stage of prophase-I in meiosis. They measure about 1500 to 2000 in length. ..

The techniques of cultivating human cells in specific media and the techniques used in somatic cell genetics have enabled geneticists to understand the biochemical basis of the inheritance of many characters. Division of the human cells in the cell culture is arrested at the met..

This type of sex determination occurs in insects and mammals including human beings. Here, the females have two identical homologous sex chromosomes designated as XX and the males have two dissimilar sex chromosomes designated as X and Y. Thus, females are ho..

Chromosome number is a species-specific character. The complete set of chromosomes in the body cell of a species is known as karyotype. For example, the 23 pairs of chromosomes found in the somatic cells represent the human karyotype. In the karyotype it is p..