how many homologous pairs of chromosomes do humans have

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. Ap..

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 ..

Let us think of a pair of contrasting character represented by the alleles R and r. A pair of homologous chromosomes carrying these alleles undergo pairing in prophase I and subsequently separate (or segregate) during anaphase I of first meiosis. In..

. 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 ..

. Hydrocarbons and their major sub groups form a homologous series of organic compounds. As an illustrative example, the simplest of all hydrocarbons is methane whose molecular formula is CH 4 . This molecule consists of a single carbon atom linked to four hydrogen atoms by single covalen..

The idea of independent assortment can be explained as follows: 1. Let us think of two pairs of contrasting characters represented by the alleles R and r, Y and y. There are two ways by which the two homologous chromosomes segregate during metaphase I of first meiosis...

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..

The number of chromosomes is fixed for a given species. It varies from a minimum of two to several hundreds in different species of plants and animals. All individuals of a given species show the same chromosome number in all their body cells. The number of chromosomes..

It has been noted that in the dihybrid genetic crosses, a recombination frequency of less than 50% indicates linkage of the two genes involved. Morgan and Sturtevant found that the recombination frequency varies for different mutant gene pairs. The difference in the recombination frequenc..

The exact number of somatic chromosomes in man was not known till 1956. New techniques of staining chromosomes have revealed the exact number and this have greatly helped the study of human genetics. Using the karyotyping techniques the form, shape and size of all the ..