Biology and SexChromosomal Sex

Chromosomal Anomalies

Biology and SexChromosomal Sex

Chromosomal Anomalies

KEY CONCEPTS• Chromosomal Sex

• The Basics: 46 Chromosomes, Two Sex Chromosomes, X’s And Y’s• Andosperm and Gynosperm• The Problematic X Chromosome and Sex-Linked Traits

• Chromosomal Anomalies• Errors in cell division lead to extra or missing chromosomes• Turner’s Syndrome (X Ø) Ø)• Trisomy X Syndrome (XXX)• Klinefelter’s Syndrome (XXY or even XXXY)• Supernumerary Y Syndrome (XYY)

OvumOvum SpermSperm

Each contributes 23 chromosomes for a total of 46Each contributes 23 chromosomes for a total of 46

Always an XAlways an X An X or a YAn X or a Y

X ChromosomeX Chromosome Y ChromosomeY Chromosome

XX - FemaleXX - Female XY - MaleXY - Male

OvumOvum SpermSperm

Each contributes 23 chromosomes for a total of 46Each contributes 23 chromosomes for a total of 46

Always an XAlways an X An X or a YAn X or a Y

Y-AndospermX-Gynosperm

XX - FemaleXX - Female XY - MaleXY - Male

THE PROBLEMATIC X CHROMOSOMETHE PROBLEMATIC X CHROMOSOMEPathological Sex-Linked TraitsPathological Sex-Linked Traits

Hemophilia Hemophilia • Color Blindness • Muscular Dystrophy

KEY CONCEPTS• Chromosomal Sex

• The Basics: 46 Chromosomes, Two Sex Chromosomes, X’s And Y’s• Andosperm and Gynosperm• The Problematic X Chromosome and Sex-Linked Traits

• Chromosomal Abnormalities• Errors in cell division lead to extra or missing chromosomes• Turner’s Syndrome (X Ø) Ø)• Trisomy X Syndrome (XXX)• Klinefelter’s Syndrome (XXY or even XXXY)• Supernumerary Y Syndrome (XYY)

XX - FemaleXX - Female XY - MaleXY - Male

Trisomy XTrisomy XSyndromeSyndrome

Turner’sTurner’sSyndromeSyndrome

In the absence of a “Y” chromosome, these are females.In the absence of a “Y” chromosome, these are females.

Supernumerary YSupernumerary YSyndrome Syndrome

Klinefelter’s Klinefelter’s SyndromeSyndrome

In the presence of a “Y” chromosome, these are males.In the presence of a “Y” chromosome, these are males.They are “Pseudo-hermaphrodites”They are “Pseudo-hermaphrodites”