NondisjunctionNondisjunction Failure of sister chromatids or homologous

chromosomes to separate during Mitosis or Meiosis (metaphase 1 & 2)

This could result to a condition wherein the daughter cells have an abnormal number of chromosomes; one cell having too many chromosomes while other cell having none.

Trisomic- having three of one type of chromosome (1 extra) 2n+1

Monosomic- having a single chromosome instead of a pair (2n-1) (Turners)

Aneuploidy- is a condition in which the chromosome number is not an exact multiple of the haploid number of a particular species.

Autosomal chromosomes-Any chromosome except for the sex chromosomes. Humans have 44 autosomal chromosomes, or autosomes

Sex chromosomes- the 23rd pair of chromosomes determine the gender of the offspring

• Polyploidy-the condition in which a Polyploidy-the condition in which a normally diploid cell or organism acquires normally diploid cell or organism acquires one or more additional sets of one or more additional sets of chromosomes. Polyploidy is common chromosomes. Polyploidy is common among plants and has been, in fact, a among plants and has been, in fact, a major source of speciation in the major source of speciation in the angiospermsangiosperms

PlantProbable ancestral haploid number

Chromosomenumber Ploidy level

domestic oat 7 42 6n

peanut 10 40 4n

sugar cane 10 80 8n

banana 11 22, 33 2n, 3n

white potato 12 48 4n

tobacco 12 48 4ncotton 13 52 4napple 17 34, 51 2n, 3n

Human Human male male karyotypkaryotype, e, written written as as 46 46 XYXY

Human Human female female karyotypkaryotype, e, written written as as 46 46 XXXX

Jacob’s syndromeJacob’s syndrome

XYYNo abnormal

appearance/behaviorfertile

Jacob’s SyndromeJacob’s Syndrome1 in 1,800 births

47 chromosomesXYY only

47XYY

#23 Trisomy Nondisjunction

Jacob’s SyndromeJacob’s Syndrome

Normal physicallyNormal mentallyIncrease in testosteronePerhaps more aggressiveNormal lifespan

Klinefelter’s SyndromeKlinefelter’s Syndrome

XXY, male

Klinefelter’s SyndromeKlinefelter’s Syndrome1 in 1,100 births

47 chromosomesXXY only

47, XXY

#23 Trisomy Nondisjunction

Klinefelter’s Klinefelter’s SyndromeSyndrome

Scarce beardLonger fingers and armsSterileDelicate skinLow mental abilityNormal lifespan

Patau Patau syndromesyndrome

47, XX, +13

Patau’s Trisomy Patau’s Trisomy SyndromeSyndrome

1 in 14,000 births

47 chromosomesXY or XX

47, +13

#13 Trisomy Nondisjunction

Small headSmall or missing eyesHeart defectsExtra fingersAbnormal genitaliaMentally retardedCleft palateMost die a few weeks after birth

Patau’s Trisomy Patau’s Trisomy SyndromeSyndrome

Down SyndromeDown Syndrome47, XY, +21

1 in 1,250 births

47 chromosomesXY or XX

#21 Trisomy Nondisjunction

Down Syndrome

Down SyndromeDown Syndrome

Short, broad hands Stubby fingersRough skinImpotency in malesMentally retardedSmall round faceProtruding tongueShort lifespan

Edwards SyndromeEdwards Syndrome47, XY, +18

Edward’s Trisomy Edward’s Trisomy SyndromeSyndrome

1 in 4,400 births

47 chromosomesXX=80%

XY=20%

#18 Trisomy Nondisjunction

Edward’s Trisomy SyndromeEdward’s Trisomy Syndrome

Small headMentally retardedInternal organ abnormalities90% die before 5 months of age

Turners SyndromeTurners Syndrome

45, X

Turners SyndromeTurners Syndrome

96-98% do not survive to birthNo menstruationNo breast developmentNo hipsBroad shoulders and neck

Trisomy 16, monosomy XTrisomy 16, monosomy X

46, X, +16Not viable beyond 1st

trimester

Trisomy XTrisomy X47 XXX symptoms

1/1000healthy and fertile -

cannot be distinguished from normal female except by karyotype

Robertsonian Translocation Robertsonian Translocation 13-1413-14

Several types, with varying results.

Wolf Hirshhorn SyndromeWolf Hirshhorn Syndrome4p- Very rare. Affected children are small, with microcephaly

and abnormal facies. There are cardiac, renal, and genital abnormalities. Most are stillborn or die in infancy.

Cri-du-chat SyndromeCri-du-chat Syndrome

5p- site

Moon-shaped faceHeart diseaseMentally retardedMalformed larynxNormal lifespan

Aniridia-Wilms Tumor Aniridia-Wilms Tumor SyndromeSyndrome

1 in 50,000,000 births

46 chromosomesXY or XX

#11 Deletion of upper arm

Aniridia-Wilms Tumor SyndromeAniridia-Wilms Tumor Syndrome

Mentally retardedGrowth retardedBlindnessTumors on kidneysShort lifespan

Thirteen Q Deletion Thirteen Q Deletion SyndromeSyndrome

1 in 500,000 births

46 chromosomesXY or XX

#13 Deletion of lower arm

Thirteen Q Deletion SyndromeThirteen Q Deletion SyndromeMentally retardedDeformed faceNo thumbsHeart diseaseShort lifespan

Prader-Willi Prader-Willi SyndromeSyndrome

1 in 5,000,000 births

46 chromosomesXY=97% XX=3%

#15 Deletion of lower arm

Prader-Willi SyndromePrader-Willi Syndrome

Small bird-like headMentally retardedRespiratory problemsObesityShort lifespan

Eighteen Q Deletion Eighteen Q Deletion SyndromeSyndrome

1 in 10,000,000 births

46 chromosomesXY or XX

#18 Deletion of lower arm

Eighteen Q Deletion SyndromeEighteen Q Deletion SyndromeMentally retardedHeart diseaseAbnormal hands and feetLarge eyesLarge earsNormal lifespan

Cat-Eye SyndromeCat-Eye Syndrome1 in 1,000,000 births

46 chromosomesXY or XX

#22 Deletion of bottom arm

Cat-Eye SyndromeCat-Eye Syndrome

Fused fingers and toesMentally retardedSmall jawHeart problemsNormal lifespan

Four-Ring SyndromeFour-Ring Syndrome1 in 10,000,000 births

46 chromosomesXY or XX

#4 Inversion

Four-Ring SyndromeFour-Ring Syndrome

Cleft palateClub feetTestes don’t descendShort lifespan

Triple X SyndromeTriple X Syndrome1 in 2,500 births

47 chromosomesXXX only

#23 TrisomyNondisjunction

Triple X SyndromeTriple X Syndrome

Normally physically

Normal mentallyFertile