Male vs Female Chromosomes
Male and female chromosomes are the sex determining chromosomes of an organism. These are also known as gonosomes. Numerous models are used for sex determination in organisms. XY system is used by humans, most mammals, some insects, and some plants. Other mechanisms available are XO system and ZW system. In XO system, the sex is determined by the absence or presence of a second X chromosome and, in ZW system, the sex is temperature dependent. In humans, 22 pairs of autosomes and one pair of gonosomes are present. X chromosome is female chromosome and Y chromosome is male chromosome. If the fetus has XX, a female is born and if XY, a male. Therefore, it is clear that the main factor for sex determination is the presence of Y chromosome.
Male chromosome or Y chromosome contains many genes determining various characteristics. It contains less genetic material when compared to X chromosome. Y chromosome also contains unique male genes which are absent on the X chromosome. One such gene is SRY gene in humans. However not all male specific genes are located on the Y chromosome. Some males are born as XXY, and they may show some female physiological characteristics. This disorder is known as Kleinefelter’s syndrome. Some males are born as XYY, and they are known as ‘super’ men usually showing very aggressive male behavior.
Some diseases are sex specific or sex linked. Many of these are phenotypically observable in males. Sex differences such as body hair growth, breasts and mammary glands development, growth of genitals etc. could be either direct or indirect. Direct sex differences, which are usually observable from birth and before puberty, are determined by Y chromosome. The indirect sex differences come from hormones.
Female chromosome also known as X chromosome also contains many genes responsible for both sexual and non-sexual characteristics. Many diseases that a phenotypically observable in males are hidden in females due to the presence of two X chromosomes, thereby making them carriers for many sex determined diseases. Genetic disorders determined by X genes are called X linked diseases.
If a woman possesses XXX, it is known as triple X syndrome where she has an average IQ and is usually taller than other women. If a woman has only one X chromosome it is called Turner’s syndrome where she is shorter, infertile and lower in IQ level. X chromosome is larger than the Y chromosome.
What is the difference between Male and Female Chromosomes?
• In humans, a male is born if both X and Y chromosomes are present, and a female is born if both the chromosomes are X.
• X chromosome is larger than the Y chromosome.
• Two X chromosomes can have complete chromosomal pairing, but X and Y chromosomes have incomplete chromosomal pairing since Y is smaller.
• X chromosome has more than 1000 working genes, but a Y chromosome has less than 100 working genes.
• Sex abnormalities connected to X and Y chromosomes are different from each other.