sex linkage (1 Viewer)

[lkc03]

oki have read about morgans experiments about sex linkage but for some reason i cant comprehend the idea can some please explain it really simply?!

 

[Sofstar]

This is what i had down in my notes. Hope that it helps in a way.

He used these fruit flies as they can breed easily in captivity, require little space, produce a large number of offspring and the two sexes can be easily identified. Among the red-eyed flies, he noticed a male fruit fly with white eyes. He then crossed this white-eyed male with a pure breeding red-eyed female. The F1 flies all had red eyes. However in the F2 generation, there was a mix of red-eyed and white-eyed fruit flies. When Morgan took a closer look, he found that the flies with the white eyes were all males.

He concluded that the gene producing the white-eyed phenotype were located on the X chromosome of Drosophila

 

[Buiboi]

well i dont think you really need the precise details on the experiment itself
but rather the main idea of it

thefact that he tested eye colour, red and white, among male and female flies and considering that the flies did not produce simple mendelian ratios, he made the assumption that the gene for the eye colour were evident on the sex chromosome


Btw, i have a question of my own....can a gene be located on a Y chromosome? or is sex linkage only on the x chromosome, cuz like in the punnet squares the Y chromosome of the male doesnt account for any trait?

Ta!

 

[cmk]

^
i think for the hsc course you only need to that know sex-linkage occurs on the x-chromosome.
i have heard or read somewhere that the y chromosome is involved for some traits (i'm pretty sure of this) but again its not necessary for the hsc.

 

[LEGENDofKOSTIN]

Perverts

 

[Buiboi]

kk gotcha!

 

[xiao1985]

hmm interesting...

if the defective gene is carried on the y chromosome, then i would assume it would no longer be sex linked.... since chromosomes cross over during meiosis.

 

[Buiboi]

^
huh?, but crossing over doesnt always occur in meiosis? waht are you saying?

my teacher told me like last yr or something that sex linkage, only refers to the X chromosome, but didnt explain anything related to the Y chromosome !?!??

 

[xiao1985]

Doesn't always occur doesn't account for the fact that EVERY part on the Y chromosome MAY subject to cross over... which means what ever maybe carried on Y, can be carried on X as well, hence NOT sex linked.

 

[Tiffanys]

damn the title made me wanna lawl at something, u let me down.

 

[PrettyVacant]

Ew, I have to learn this for Bio Olympiad.

 

[xiao1985]

damn the title made me wanna lawl at something, u let me down.

lawl... what might that be?!