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Ten sex chromosomes. Males have X 1 Y 1 X 2 Y 2 X 3 Y 3 X 4 Y 4 X 5 Y 5, females have X 1 X 1 X 2 X 2 X 3 X 3 X 4 X 4 X 5 X 5. [83] [84] 139 Upland cotton (Gossypium hirsutum) 52 This is for the cultivated species G. hirsutum (allotetraploid, 2n=4x=52). This species accounts for 90% of the world cotton production.
The basic number of chromosomes in the somatic cells of an individual or a species is called the somatic number and is designated 2n. In the germ-line (the sex cells) the chromosome number is n (humans: n = 23). [4] [5] p28 Thus, in humans 2n = 46. So, in normal diploid organisms, autosomal chromosomes are present in two copies.
46,XX/46,XY is an example of tetragametic chimerism because it requires four gametes – two sperm and two ova. 46,XX/46,XY is most commonly explained during in conception combination of two fertilized eggs zygotes. Two ova from the mother are fertilized by two sperm from the father. One sperm contains an X chromosome; the other contains a Y ...
So, humans have two sets of 23 chromosomes in each cell that contains a nucleus. One set of 23 chromosomes (n) is from the mother (22 autosomes, 1 sex chromosome (X only)) and one set of 23 chromosomes (n) is from the father (22 autosomes, 1 sex chromosome (X or Y)). Ultimately, this means that humans are diploid (2n) organisms. [2]
The number of chromosomes in the cell where trisomy occurs is represented as, for example, 2n+1 if one chromosome shows trisomy, 2n+1+1 if two show trisomy, etc. [2] "Full trisomy", also called "primary trisomy", [2] means that an entire extra chromosome has been copied. "Partial trisomy" means that there is an extra copy of part of a chromosome.
Chromosome 2 is one of the twenty-three pairs of chromosomes in humans. People normally have two copies of this chromosome. People normally have two copies of this chromosome. Chromosome 2 is the second-largest human chromosome, spanning more than 242 million base pairs [ 4 ] and representing almost eight percent of the total DNA in human cells .
Most cells in the human body have 23 pairs of chromosomes, or a total of 46 chromosomes.(The sperm and egg, or gametes, each have 23 unpaired chromosomes, and red blood cells in bone marrow have a nucleus at first but those red blood cells that are active in blood lose their nucleus and thus they end up having no nucleus and therefore no chromosomes.) [8]
A Robertsonian evolutionary fusion, which may have occurred in the common ancestor of humans and other great apes, is the reason humans have 46 chromosomes while all other primates have 48. Detailed DNA studies of chimpanzee , orangutan , gorilla and bonobo apes has determined that where human chromosome 2 is present in our DNA in all four ...