AP Biology Sex Linked Traits AP Biology Sex linked traits Genes are on sex chromosomes (pair 23) ...

AP Biology

Sex Linked Traits

AP Biology

Sex linked traits Genes are on sex chromosomes (pair 23)

as opposed to autosomal chromosomes

AP Biology

Genes on sex chromosomes

Y chromosome few genes other than SRY

SRY - Sex-determining Region of Y turns on genes for production of male hormones

X chromosome other genes/traits beyond sex determination

AP Biology

RR rr

You would think this right?

x

r r

R

R

Rr

Rr Rr

Rr

100% red eyes

Rr Rr

x

R r

R

r

RR

Rr rr

Rr

3 red : 1 white

Doesn’t workthat way!

AP Biology

XRXR XrY

But it’s not normal dominance…its sex-linked

x

Xr Y

XR

100% red eyes

XR

XRXr XRY

XRYXRXr

x

XRXr XRY

XR Y

XR

Xr

XRXr

XRYXRXR

XrY100% red females50% red males; 50% white males

AP Biology

Hemophilia

Hh x HHXHYXHXh

XHXh

XH

Xh

XHY

Y

XH

sex-linked recessive

XH Ymale / sperm

XH

Xh

fem

ale

/ eg

gs XHXH

XHXh

XHY

XhY

XHXH XHY

XHXh XhY

carrier disease

AP Biology

Colorblindness

Hh x HHXHYXHXh

sex-linked recessive

XH Ymale / sperm

XH

Xh

fem

ale

/ eg

gs XHXH

XHXh

XHY

XhY

XHXH XHY

XHXh XhY

carrier disease

AP Biology

What about

Baldness?

Great!!!!

Any Questions?