Xy = XX= female male Female karyotype Male karyotype

SEX DETERMINATION AND SEX-LINKED INHERITANCE

Sex Determination

Xy =

XX= female

male

Female karyotype

Male karyotype

X and Y chromosomes

Nondisjunction- Jigsaw

Nondisjunction: failure of chromosomes to separate during meiosis 1 or 2

Results in an extra chromosome or a missing chromosome

http://glencoe.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::550::400::/sites/dl/free/0078757134/383925/Chapter11_NGS_VisualizingNondisjunction_10_10_06.swf::Visualizing%20Nondisjunction

XO- Turner Syndrome XXX- Trisomy X XXY- klinefelter Syndrome XYY- Jacob Syndrome

Very often, symptoms are slight due to X-inactivation and the small amount of genes found on the Y chromosome

SEX CHROMOSOMES CONTAIN GENES THAT CODE FOR TRAITS

=SEX LINKED TRAITS

Both Males and Females Inherit X Chromosomes: Males XY; Females

XX

X-LINKED GENES: Genes carried on the X chromosomeHemophilia

Color blindnessBaldness Muscular Dystrophy

Mother Without hemophilia = X X

Without hemophilia = X X

With hemophilia = X X Father

Without hemophilia = X y

With hemophilia = X y

H H

H h

h h

CARRIER

H

h

Key!