How many chromosomes does a mouse somatic cell contain if the number is 40? - briefly
A mouse somatic cell possesses a diploid set of 40 chromosomes, organized as 20 homologous pairs. This number represents the complete chromosomal complement for the species' body cells.
How many chromosomes does a mouse somatic cell contain if the number is 40? - in detail
A mouse somatic cell carries a diploid complement of chromosomes, denoted as 2 n = 40. This means the nucleus contains 40 distinct chromosomal units organized into 20 homologous pairs. Each pair consists of one chromosome inherited from the mother and one from the father.
The 40 chromosomes are divided into 19 pairs of autosomes plus one pair of sex chromosomes. In males the sex pair is XY, while in females it is XX. All chromosomes are linear DNA molecules packaged with histone proteins, forming the characteristic metaphase chromosome structure observable during cell division.
During the S phase of the cell cycle each chromosome is replicated, producing two sister chromatids per chromosome. Consequently, before mitosis the cell temporarily contains 80 chromatids, but the chromosomal count remains 40 because each chromatid pair is considered a single chromosome until separation.
The mouse karyotype is routinely used as a reference in genetic research. The constant number of 40 chromosomes across somatic tissues provides a stable genetic background for studies of gene function, mutation effects, and comparative genomics.