Sex determinatiom:
Every human have 46 chromosome note that this chromosomes would determine the xteristics a child would put up...ie 22 pair of autosome and 1 pair of sex chromosome(X or Y).The sex of a child is determined based on this sex chromosome..if it is XX then it is femals and if XY it is a male.
NOTE:the Y chromosome is necessary for the appearance of testis(an organ found only in the male folks).know also that the appearancs of this testis is not sufficient for maleness;full expression of maleness would require androgenic hormones.
The short arm of Y chromosome is located in the TDG(testis determining genes) which secrete testis determining factor.The long arm secretes H-Y antigen.
What determines the sex of an individual?
1)genetic sex(GH)
2)gonadial sex(GOH)
3)phenotypic sex(PH)
Genetic sex: defines the presence or absence of Y chromosome
Gonadial sex: defines the appearance of of testis in male and ovary in female
Phenotypic sex: defines the appearance of the internal sex organ and external genitalia
MOST IMPORTANT THING TO NOTE
since the female is XX and the male is XY,the female aways has an X to give while the male is the true determiner of if the child would be male or female depending on if his giving a X or Y...so men should stop nagging when they are always getting girls...not the womans fault
Some sex chromosomal abnormalities:
During the mieotic division of garmetogenesis the sex chromosome gets paired and then are seperated to be distributed to each daughter cell...sometimes sadly this seperation does not occur(condition know as non disjunction)this results in sex chromosomal aberration...it is extimated to occur in 1 of every 200 lives
E.G of this sex chromosomal abnormality
1)turner syndrome:OX
PH:this female because of absence of Y chromosome
GOH:this female will not mature sexually
2)klinefelter's syndrome:XXY
GOH:testis
PH:thered be a condition called semineferous tubules disgenesis
3)super female: XXX
GOH:ovary
PH:every thing would be in excess hence super
4)fragile X syndrome:
Features in male most but affects the female because they are cariers.where one arm of the X is subseptible to breakage
5)XYY:
GOH:testis
PH:socking as it seems but its associated to criminal behavior
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