1) A karyotype is a profile of an individual's chromosomes arranged by size and includes the number of chromosomes. The human karyotype contains 23 pairs of homologous chromosomes for a total of 46 chromosomes. 2) Mutations in DNA can cause genetic disorders like Down syndrome, Turner syndrome, and Klinefelter syndrome. Mutations include changes in single nucleotides, entire chromosomes, or the number of chromosomes. 3) Sickle cell anemia is caused by a point mutation that substitutes one nucleotide, changing the mRNA codon and resulting amino acid produced, altering hemoglobin function. Frameshift and chromosome mutations can also disrupt genes.

1. GENOMICS:
Karyotypes &
Mutations
Seamon

2. Karyotype-
• an organized profile
of chromosomes
• arranged and
numbered by size
from largest to
smallest

3. HUMAN KARYOTYPE
• 23 PAIRS of
chromosomes
called
homologous
chromosomes
• 1 chromosome
from each parent
• That makes 46 total
chromosomes

4. HUMAN KARYOTYPE
• autosomes-
chromosomes 1-22
• sex chromosomes
• chromosome 23
• X = female
• Y = male

5. Karyotypes show us…
• sex of the individual
• genetic disorders caused by too few or too
many of a chromosome

6. Nondisjuction
too many or too few chromosomes are caused
by a mistake in meiosis

7. Trisomy-21
• three of #21
• likelihood of
Downs Syndrome
increases with
mother’s age
DOWNS SYNDROME

8. • delayed physical
and mental
development
• flattened face &
eyes slanted
upward

9. Female with a
single X
• ovaries do not
develop
• do not mature
sexually
TURNER SYNDROME

10. Male with an extra X
• less facial hair and
muscles
• no sperm
KLINFELTER SYNDROME

11. Mutations-
• a change in the DNA
• causes changes in genetic code
• can be…
• an entire chromosome
• in any cell
• harmless, beneficial or harmful
• natural or environmental (radiation, chemicals)
• only passed to the next generation when
changes occur in the sex cells or gamete
• lead to genetic variation
• EXAMPLE: PTC tasters/non-tasters

12. PTC tasters & non-
tasters
• some people can
taste this bitter
chemical while
others cannot
• it’s genetic
• tasters & non-tasters
have slightly different
receptors (proteins)
on taste buds for
bitter taste

13. CCG and CCG
GTA and CCG
GTA and GTA
Tasters
Medium Tasters
Non-Tasters
A change in DNA causes
• change in the protein
• which causes a change in function

14. Gene Mutations
• may involve large areas of DNA or a single
nucleotide
• Point Mutation (of a single nucleotide)
• substitution
• duplication
• deletion
• mutation can code for the wrong amino acid,
leading to difference in function

15. What is the mRNA codon that would pair with a
DNA sequence of CTC?
The paired mRNA codon is GAG
What is the amino acid that it receives?
glutamic acid
THIS IS WHAT HAPPENS IN A NORMAL CELL
SICKLE CELL ANEMIA
TAKE OUT YOUR CODON CHART

16. In sickle Cell anemia, in CTC the T gets substituted
with an A resulting in CAC
What is the mutated mRNA codon?
The paired mRNA codon is GUG
What is the mutated amino acid that it receives?
For a mutated (substituted) DNA sequence, the
paired mRNA codon is Valine WRONG AMINO ACID
makes the wrong protein
SICKLE CELL ANEMIA

18. Frame shift mutation
• point mutation
• a nucleotide is deleted or inserted
• all codons after that are affected… the frame
shifts
• subsequent reading gives a nonsense
sequence of amino acids

19. ACTIVITY
• THE OLD RED DOG WAS TOO BIG FOR HIS BED
• Deletion that would delete the D in OLD…
• THE OLR EDD OGW AST OOB IGF ORH ISB ED
• Inversion of the word DOG...
• THE OLD RED GOD WAS TOO BIG FOR HIS BED
19
FRAME SHIFT- confuses the
whole message: bad mutation
less of a problem

20. Chromosome Mutations
MEIOSIS-
• crossing over- pieces of chromosomes are
exchanged
• another source of genetic variation
• new combinations of genes

21. Translocation
• chromosome
mutation
• fragments trade
with the wrong
chromosome
• not always a
problem

22. Deletion
• fragment is lost
(often in
translocation)
• Cri du Chat-
deletion in
chromosome 5;
infants have the
‘cry’ of a cat

23. Inversion
• fragment is lost
flips around
• not always a
problem

24. Duplication
• sometimes a
piece is repeated
• chromosome #4
has CAG repeated
10 to 30 times

25. • Gene has too
many repeats of
CAG
• Forms a protein
that clumps in
the brain and
kills nerve cells
• protein formed
does not work
properly
HUNTINGTON’S DISEASE (40 or more repeats)

26. Huntington’s Disease (HD)
• Early symptoms are forgetfulness and
irritability in 30’s or 40’s
• Progressive deterioration of the nervous
system
• Leads to loss of muscle control and eventually
death
• Because of late onset, it is passed on
unknowingly.

27. • traits found on the sex chromosomes (X & Y)
• carrier- “carries” the gene but does not have
the disease (often on X chromosome)
X-linked: genes on the X chromosome.
Y-linked: genes on the Y chromosome.
Most are recessive traits
Sex-Linked Traits

28. EXAMPLES
• baldness
• hemophilia
• muscular dystrophy
• red-green color
blindness
Sex-Linked Traits
red-green color blindness

29. Color-blindness is recessive.
B = normal
b = colorblind
Father is colorblind. His wife is not.
Father’s genotype is _____
Mother’s genotype is _____
What is the likelihood of them having a
colorblind son? Colorblind daughter?
XbY
XBXB

30. • X-Linked Trait
• blood does not clot
properly
• Any one of several
mutations on
genes for clotting
factors
• Treatment involves
replacing defective
clotting factor
HEMOPHILIA