Gorilla
12-12-2005, 12:58 AM
http://www.ncbi.nlm.nih.gov/books/bv.fcgi?call=bv.View..ShowSection&rid=gnd.section.156
SRY (which stands for sex-determining region Y gene) is found on the Y chromosome. In the cell, it binds to other DNA and in doing so distorts it dramatically out of shape. This alters the properties of the DNA and likely alters the expression of a number of genes, leading to testis formation. Most XX men who lack a Y chromosome do still have a copy of the SRY region on one of their X chromosomes. This copy accounts for their maleness. However, because the remainder of the Y chromosome is missing they frequently do not develop secondary sexual characteristics in the usual way.
Two pairs of 23 chromosomes join together during fertilization to produce an embryo. What determines the sex of the embryo is whether the father contributes a XXXXXXXXXXXXXXXXXXXXXXY or a XXXXXXXXXXXXXXXXXXXXXXX-the gene controlling sexual selection residing on the Y, potentially making the child a male.
Females always contribute 23 X's, with no gene anywhere controlling sex selection, and thus, female humans always contribute 23 autosomes.
Want to know something funny? Either the HGP doesn't know this, or they are covering up something (less likely)- http://www.ornl.gov/sci/techresources/Human_Genome/project/info.shtml
-Vaszoly
22 autosomes + X + Y = 24 disparate chromosomes
There is one autosome, always contributed by the male.There is NO gene on any female X chromosome that determines sex, making it an autosome. Vaszoly, I have a question-what makes any female chromosome into a sex autosome, considering that an 'x and Y' never combine in isolation, but do so in pairs of 23 (coughs at 24 :p)?
;)
SRY (which stands for sex-determining region Y gene) is found on the Y chromosome. In the cell, it binds to other DNA and in doing so distorts it dramatically out of shape. This alters the properties of the DNA and likely alters the expression of a number of genes, leading to testis formation. Most XX men who lack a Y chromosome do still have a copy of the SRY region on one of their X chromosomes. This copy accounts for their maleness. However, because the remainder of the Y chromosome is missing they frequently do not develop secondary sexual characteristics in the usual way.
Two pairs of 23 chromosomes join together during fertilization to produce an embryo. What determines the sex of the embryo is whether the father contributes a XXXXXXXXXXXXXXXXXXXXXXY or a XXXXXXXXXXXXXXXXXXXXXXX-the gene controlling sexual selection residing on the Y, potentially making the child a male.
Females always contribute 23 X's, with no gene anywhere controlling sex selection, and thus, female humans always contribute 23 autosomes.
Want to know something funny? Either the HGP doesn't know this, or they are covering up something (less likely)- http://www.ornl.gov/sci/techresources/Human_Genome/project/info.shtml
-Vaszoly
22 autosomes + X + Y = 24 disparate chromosomes
There is one autosome, always contributed by the male.There is NO gene on any female X chromosome that determines sex, making it an autosome. Vaszoly, I have a question-what makes any female chromosome into a sex autosome, considering that an 'x and Y' never combine in isolation, but do so in pairs of 23 (coughs at 24 :p)?
;)