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NEL Molecular Genetics 693

Section20.4

SUMMARY Mutations and Genetic Variation

Table 2 Types of Mutations

Category Type

point mutation substitution

AAG CCC GGC AAA

AAG ACC GGC AAA

deletion

AAG CCC GGC AAA

AAC CCG GCA AA

insertion

AAG CCC GGC AAA

AAG ACC GGG CAA A

chromosomal translocation

chromosome 1 5 
AAATTCG GCACCA 3


chromosome 2 5 
TAGCCC AAGCGAG 3 

chromosome 1 5 
TAGCCC GCACCA 3


chromosome 2 5 
AAATTCGAGCGAG 3 


inversion

normal chromosome 5 
AATTGGCCATA ATATGAA AAGCCC 3


3 
TTAACCGGTAT TATACTT TTCGGG 5 

after inversion 5 
AATTGGCCATATTCATAT AAGCCC 3


3 
TTAACCGGTATAAGTATATTCGGG 5 

Result

missense mutation

only one amino acid substituted

frameshift mutation

can result in many different

amino acids substituted or a stop

codon read (nonsense mutation)

inactivation of gene if

translocation or inversion is

within a coding segment

• In mammals, mitochondrial DNA can be used to trace inheritance through the
  maternal lineage.


• Comparisons of DNA sequences can provide detailed phylogenetic relationships
  by revealing the specific changes in the genetic makeup of species and
  populations.


• SINEs and LINEs provide excellent inheritable markers for tracing the evolution
  of species’ lineages.