Chromosomes are thread-like molecules that contain genetic information about the whole organism, from the color of the eye to the length of the body.
Did you know? There are over 1000 genes on the Y chromosome and less than 200 on the X chromosome.
Chromosomes comprise a protein and a single DNA molecule that contains the body’s genetic information – an inheritance from its parents.
In humans, animals and plants, most chromosomes are arranged in pairs and in the nucleus of a cell. Humans have 22 pairs of such chromosomes, called autosomes.
Humans have an additional pair of chromosomes that determine gender for 46 chromosomes. The sex-determining chromosomes are called the X and Y chromosomes, and their combination determines whether the embryo develops into a female or male child.
Usually women have two X chromosomes, but men have X and Y chromosomes. It forms the combination when the sperm fertilize the egg. Egg and sperm differ from other cells in the body because they have only one chromosome.
These cells are called gametes, or germ cells, and they occur during the process of meiosis – the division of cells when new cells contain only half of the “parent” cell – so when a cell divides, two gametes are usually formed.
All maternal ovum gametes have the X chromosome, but we find both gametes with the X chromosome and gametes with the Y chromosome in a similar proportion in the father’s semen.
Spermatozoa is the unknown in determining a baby’s sex – if the sperm that fertilizes the egg contains the X chromosome, a female zygote will form in combination. If there is a Y chromosome in the spermatozoon, it will form a male baby.
During fertilization, the gametes in the sperm, together with those in the ovum, form a zygote, but it has two sets of 23 chromosomes, for 46 chromosomes.
But not always. Recent studies have shown that different combinations of germ cell chromosomes are possible in human genes, especially in people who belong to sexual minorities.
X chromosome Xq28 and with 8. chromosome connected gene usually are found in homosexual males.
One in 1,000 babies is born with a single sex chromosome (45X or 45Y) – a condition called monosomy. Other times, a baby with three or more sex chromosomes is born, and we call this a polysomy.
Some men are born with the 46XX chromosome – because there is a small deviation in the Y-chromosome region. But few women are born with the 46XY chromosome because of Y chromosome mutations.
We cannot accept as an absolute statement that women always have a combination of XX chromosomes, but men XY. Rather, sex is determined by different chromosomal variations, chromosome balance, and phenotypic variations.
The definition of gender and gender is different, and in many cultures there are more terms for identifying a person than just “woman” or “man.”