2.  A mutation is a change in a gene
 A mutation can only be inherited in it
occurs in a sex cell
 Effects of mutations can be:
› Positive
› Negative
› Neutral

3.  Deletion – loss of a
piece of a
chromosome

4.  Inversion – piece of
a chromosome
breaks off, flips
around, and
reattaches

5.  Translocation – a
piece of one
chromosome breaks
off and reattaches
to a nonhomologous
chromosome

6.  Nondisjunction – chromosome fails to
separate from its homologue during
meiosis

7.  Point Mutation – one nucleotide is
changed in the DNA sequence
› Substitution
› Deletion
› Insertion

8.  Substitution – one
nucleotide replaces
another

9.  Deletion – one or
more nucleotides
are deleted

10.  Insertion – one or
more nucleotides
are added to a
gene

11.  Deletion and insertion mutations can
both result in frameshift mutations, where
all amino acids downstream change

12.  Genetic screening – examination of a
person’s genetic makeup
› Karyotypes, tests for proteins, DNA tests
 More than 200 genetic disorders can
now be detected in the fetus

13.  Amniocentesis –
removal of amniotic
fluid from around the
fetus between the
14th and 16th week of
pregnancy

14.  Chorionic villi
sampling - A sample
from the zygote
between the 8th and
10th week of
pregnancy

15.  Genetic counseling – the process of
informing a person or couple about their
genetic makeup
› Informs individuals about problems that
might affect their offspring
› Predicts the likelihood that a couple will
produce an affected child

16.  Treat the symptoms
 Prevent symptoms

17.  Gene therapy – technique that places a
healthy copy of a gene into the cells of
a person whose copy of the gene is
defective