C-Notes: Chromosomal Abnormalities (Errors of Meiosis) Stnd: 2c C-Notes: Chromosomal Abnormalities (Errors of Meiosis) 2/14/2014 Objective: SWBAT explain the problems with meiotic spindles not separating properly during Meiosis, which causes abnormalities in offspring.

How can genetic material be changed? Incorrect number of chromosomes Non-Disjunction (Chromosomal Aberration) Problems with meiotic spindle causes the homologous chromosomes NOT to separate properly during Meiosis I Or sister chromatids fail to separate during Meiosis II Leading to TOO MANY or TOO FEW chromosomes in one daughter cell. either an extra or missing chromosome causing Aneuploidy (wrong # of chromosome. Ex: XXX) Found in Chromosomes # 8,12,13,14,15,18, & 21) Breakage of Chromosomes Deletion Duplication Inversion translocation Certain drugs have become popular among teens and young adults at dance clubs and raves.

Changes in chromosome structure deletion loss of a chromosomal segment duplication repeat a segment inversion reverses a segment translocation move segment from one chromosome to another error of replication error of crossing over

Certain drugs have become popular among teens and young adults at dance clubs and raves.

How do changes in the genetic material (alteration of chromosomes) of an organism lead to changes in the traits of that organism? This leads to gametes with irregular numbers of chromosomes. Certain drugs have become popular among teens and young adults at dance clubs and raves.

How does these alteration of chromosomes effect an organism? Baby has wrong number of chromosomes “SOMY” means Mutations Involve individual extra/missing chromosomes Usually result in early miscarriage Certain drugs have become popular among teens and young adults at dance clubs and raves.

Because it does NOT result in miscarriage 3 copies of Chromosome 21 Why is the extra # 21 chromosomemore tolerated by organisms ? (Down Syndrome) Because it does NOT result in miscarriage 3 copies of Chromosome 21 Characteristic of facial appearance and other varying effects Varying levels of retardation Frequently correlates with age of mothers.   Certain drugs have become popular among teens and young adults at dance clubs and raves.

Down syndrome & age of mother Mother’s age Incidence of Down Syndrome Under 30 <1 in 1000 30 1 in 900 35 1 in 400 36 1 in 300 37 1 in 230 38 1 in 180 39 1 in 135 40 1 in 105 42 1 in 60 44 1 in 35 46 1 in 20 48 1 in 16 49 1 in 12 Rate of miscarriage due to amniocentesis: 1970s data 0.5%, or 1 in 200 pregnancies 2006 data <0.1%, or 1 in 1600 pregnancies

Human development (body cells/ Autosomes) (chromosome #1-22) are more tolerant of wrong numbers than Sex Chromosome (pair #23/ X & Y) But abnormalities in Sex Chromosomes produces a variety of distinct syndromes in humans XXY = Klinefelter’s syndrome male XXX = Trisomy X female XYY = Jacob’s syndrome male XO = Turner syndrome female What are the Sex Chromosomes abnormalities? Certain drugs have become popular among teens and young adults at dance clubs and raves.

Sterile (cant have kids) Associated with heart defects What is Turner’s Syndrome: Monosomy X? XO Females Phenotypically female (short stature, swelling, broad chest, webbed neck, los set ears, etc) Sterile (cant have kids) Associated with heart defects Certain drugs have become popular among teens and young adults at dance clubs and raves.

XXY Male What is Klinefelter’s syndrome? one in every 2000 live births have male sex organs, but are sterile feminine characteristics some breast development lack of facial hair tall normal intelligence Certain drugs have become popular among teens and young adults at dance clubs and raves.

Klinefelter’s syndrome How many Barr bodies would you expect?

XYY Males What is Jacob’s syndrome? 1 in 1000 live male births extra Y chromosome slightly taller than average more active normal intelligence, slight learning disabilities delayed emotional immaturity normal sexual development Certain drugs have become popular among teens and young adults at dance clubs and raves.

XXX Females What is Trisomy X? 1 in every 2000 live births produces healthy females Why? Barr bodies all but one X chromosome is inactivated Certain drugs have become popular among teens and young adults at dance clubs and raves.