Sex for the purposes of this class refers to 4 components Gonadal sex Gonads or where gametes are produced by meiosis Somatic sex Somatic cells are cells that undergo mitosis. They can be divided into primary and secondary characteristics Secondary somatic sex characteristics are divided further into hair and body Sexual identification Sexual orientation
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Sex for the purposes of this class refers to 4 components Gonadal sex Gonads or where gametes are produced by meiosis Somatic sex Somatic cells are cells.
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Sex for the purposes of this class refers to 4 components
Gonadal sex
Gonads or where gametes are produced by meiosis
Somatic sex
Somatic cells are cells that undergo mitosis.
They can be divided into primary and secondary characteristics
Secondary somatic sex characteristics are divided further into hair and body
Sexual identification
Sexual orientation
FOR HUMAN MALESGonadal sex
Consists of the testes where the gametes or sperm are produced
Somatic sex characteristicsPrimary and Secondary
Male primary somatic sex characteristics penis and scrotum
Male secondary somatic sex characteristicsHair
facial hair chest hair body hairBodypelvic build straight hipsmuscular build upper body
Ability to generate muscle mass at a faster rate than females following puberty
FOR HUMAN FEMALESGonadal sex
Ovaries where eggs are produced
Female primary somatic sex characteristics
Clitoris, labia, vagina, cervix, uterus, fallopian tubes, and the ability to bear children
Female secondary somatic sex characteristicsHair vellus rather than terminal hair
Body
rounded hips, breasts, ability to nurse offspring, menstrual cycle, increased body fat composition, decreased upper body strength, decreased ability to generate muscle mass at a fast rate
Y chromosome is small and gene poor and prone to deletionSince the Y can not recombine with X, its genes began to rotGenes decayed except for SRY and the tipsThe Y is degrading fast, losing genes at the rate of 5/million yearsMay have a way out of complete degredationMany of the DNA segments are palindromes
Individuals with unusual chromosome combinations provide a clue:
X0 XXY XY femalesXX males
Female with Turner syndromeMale with Klinefelter syndrome
=> Y chromosome determines gender.
SRY gene missingSmall bit of Y with SRY gene present
=> SRY gene on Y chromosome determines gender.
KLINEFELTER
Klinefelter males have an extra X chromosome so they karyotype as XXY males
Occurs 1/1000 live births
1940 Harry Klinefelter at Massachusetts General Hospital described a syndrome occurring in males not usually detected until after puberty
KLINEFELTER
The testes are atrophied and do not produce much testosterone
The level may be so low as to be about the same amount as the estrogen produced by the adrenal cortex
Because the level is so low during puberty these individuals do not undergo normal development of male secondary sex characteristics, including muscular upper body, narrow hips and chest and facial hair
KLINEFELTER
If treated during puberty with testosterone then breast development will stop and the hips will narrow and become more male like
They will develop muscular upper bodies, broad shoulders, square jaw and deep voices
Remain sterile because the undeveloped testes can not produce sperm
But outwardly they will look like normal males
XYY MALES
1965 Jacobs in Scotland looked at the chromosomes of 197 mentally subnormal males with violent tendencies
They found 7 of those males had a 47 XYY karyotype
7/197 = 1/28 a much higher ratio than among other groups of males tested
XYY occurs 1/1000 live births
Among tall males about 1/325
Among tall penal inmates 1/30
XYY MALES
XYY males are over represented in mental and penal institutions
Large scale study done by the Danish government suggested that tall males with lower intellectual function are more likely to be convicted of crimes regardless of their karyotype
XYY karyotype is over represented in tall males 1/325