Download Karotype Chromosomal Abnormalities

DO NOW
Are genetic differences good?
In your groups, brainstorm 3
reasons why genetic diversity can
be beneficial
KARYOTYPE &
CHROMOSOME
IRREGULARITIES
Karyotype



A picture of chromosomes used to
detect chromosomal abnormalities.
Autosomal (somatic): Pairs 1-22
Sex: Pair 23
Non-disjunction Mutations
CAUSE: Chromosomes don’t separate
correctly during anaphase
EFFECT: gametes with irregular
chromosome number
replication

error of
error of

crossing over
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
Single Chromosome Mutations
Autosomal Chromosomes:
1.
Down Syndrome- Trisomy #21
Sex Chromosomes:
1.
Turner’s Syndrome (X)- Monosomy X
2.
3.
4.

Female, sterile, heart defects

Male, but have some female characteristics (Extra
breast tissue)
Kleinfelter’s Syndrome (XXY)
Jacob’s Syndrome (XYY)

Not huge effect, problems in testes fertility

Not a problem, every x chromosome except 1 is
turned into an inactive, Barr Body
XXX
1.
Ex. Calico Cats always female
Klinefelter’s Syndrome- XXY
Turner syndrome- X_
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
Barr Body
Chromosome Set Mutations



Extra Sets = “ PLOIDY”
Common in plants/fungi, usually not
successful in animals
Can lead to evolution!
PROKARYOTIC
GENETIC EXCHANGE
Prokaryotic Genetics




Haploid
Reproduce by Binary Fission
Reproduce, and MUTATE very easily
Bacterial Conjugation: “Sex Pilus”
connects 2 cells & passes genetic
material
 Genetics
recombine
Plasmid


Prokaryotes have 1 circular
chromosomes AND small DNA
molecules called PLASMIDS
Plasmids move easily during Conjugation
HUMANS ARE COOL, BUT
WHY IS IT BETTER TO BE
A BACTERIA?
Genetic changes increase
survival and can lead to
evolution!