Karyotypes Karyotypes
Jan 02, 2016
KaryotypesKaryotypes
What are they?What are they?
A “picture” of a person’s 46 A “picture” of a person’s 46 chromosomes. chromosomes.
Chromosomes are arranged Chromosomes are arranged in homologous pairs.in homologous pairs.
Homologous pairs – Homologous pairs – chromosomes of the same chromosomes of the same size and shape, but are size and shape, but are notnot genetically idenitcal.genetically idenitcal.
Why use karyotypes?Why use karyotypes?
To determine sex:To determine sex: Male- XYMale- XY Female- XXFemale- XX
To see abnormalities in To see abnormalities in chromosomeschromosomes
Extra chromosomesExtra chromosomes Missing chromosomesMissing chromosomes Extra/missing pieces of Extra/missing pieces of chromosomeschromosomes
Normal KaryotypeNormal Karyotype
What’s the problem?What’s the problem?
Turner Syndrome Turner Syndrome 45, X0 – 45 45, X0 – 45
chromosomes, only chromosomes, only 1 X chromosome1 X chromosome
Sex: femaleSex: female Symptoms: Symptoms:
– Short stature Short stature – swelling of the hands swelling of the hands
and feet and feet – Low hairline Low hairline – Low-set ears Low-set ears – Reproductive Reproductive
sterility sterility
What’s the problem?What’s the problem?
Klinefelter's syndromeKlinefelter's syndrome
47, XXY47, XXY Sex: MaleSex: Male Symptoms:Symptoms:
– SterilitySterility– Youthful buildYouthful build– ““round body”round body”
What’s the problem?What’s the problem?
Down SyndromeDown Syndrome Trisomy 21 (three Trisomy 21 (three
copies of chromosome copies of chromosome #21)#21)
Symptoms:Symptoms:– head may be smaller head may be smaller
than normal & than normal & abnormally shaped. abnormally shaped.
– a flattened nosea flattened nose– protruding tongueprotruding tongue– upward slanting eyesupward slanting eyes– short hands and fingersshort hands and fingers
What’s the problem?What’s the problem?
Edward’s SyndromeEdward’s Syndrome
Trisomy 18 Trisomy 18 Symptoms:Symptoms:
– Failure to growFailure to grow– Low set, malformed Low set, malformed
earsears– Abnormalities in the Abnormalities in the
bones of the hands and bones of the hands and feetfeet
– Kidney and heart Kidney and heart defectsdefects
InterphaseInterphase
Cell duplicates DNACell duplicates DNA Individual Individual
chromosomes not yet chromosomes not yet visible.visible.
CANCERCANCER
What is it?What is it?
Uncontrolled cell division of Uncontrolled cell division of abnormal cells which may result in abnormal cells which may result in death.death.
MetastasisMetastasis: Cells from malignant : Cells from malignant tumors may break off and travel to tumors may break off and travel to other parts of the body, forming other parts of the body, forming new tumors.new tumors.
The Four The Four phasesphases of of MitosisMitosis
PMATPMAT
ProphaseProphase chromatin condenses
(chromosomes are now visible)
Chromosomes consist of two sister chromatids
nuclear membrane disappears
Centrosomes start to move to opposite ends (poles) of cell
spindles begin to form
MetaphaseMetaphase Spindles are fully
formed
chromosomes are attached to spindles at the centromeres
Chromosomes line up at the center (equator) of the cell
AnaphaseAnaphase
• Sister chromatids separate and move to opposite poles.
• Each chromatid is now considered an individual chromosome
TelophaseTelophase
2 nuclear envelopes reform
Chromosomes uncoil into chromatin
Spindles disappear
CytokensisCytokensis cytoplasm is divided in half
ANIMAL
PLANT
Animation of Mitosis