may be expected from the collagens, which are
made up of repetive structures that are low in
information and coded by many genes, and the
conchiolins, which are a mixture of proteins of
poorly defined structure [310]. The frozen specimen of mammoth (Mammuthus primigneius) ,
found in Siberia in 1977-1979, presented a unique
opportunity for biochemical studies on an animal
species which became extinct thousands of years
ago. Particularly interesting was the completely
preserved baby mammoth "Dima", whose age
was determined as 40000 years using 14·C dating.
However, the planned DNA analysis turned out
to be unavoidably difficult. Fossil DNAs disintegrate through ageing processes into fragments
of a few hundred base pairs; become heavily
altered chemically by loss of bases, oxidation of
pyrimidines and the growth of cross-links; and
are often contaminated with foreign DNA. Only
the polymerase chain reaction (PCR) , which
facilitates sequencing starting from minute
amounts of DNA, was able to provide molecular
evidence for the close relationship of the mammoth to the present elephant species [310]. It was
much easier to examine museum materials from
more recently extinct species. Steller's sea cow
(Hydrodamalis gigas) was discovered in 1741 on
the coast of the Komandor Islands off Kamchatka
and was already extinct by 1768. Immunological
comparisons of albumins extracted from bone
with those from the fourliving sirenians show that
Hydrodamalis separated 4-8 million years ago
from its nearest relative, Dugong dugong of the
Indo-Pacific, whilst the three manatee species of
the genus Trichechus split off 17-20 million years
ago [339]. The quagga was once the most abundant zebra species in Africa; the last specimen died
in captivity in 1883. Until recently, it was not clear
whether the quagga should be considered a separate zebra species or the southern type of Equus
burchelli. Proteins extracted from quagga skin in
fact showed much more similarity to plasma proteins of E. burchelli than to the other two zebra
species, E. zebra and E. grevyi [252]. Whereas
partial sequences of quagga and E. burchelli
mtDNA are identical, those of the horse E. cabalIus contained 11 synonymous substitutions [172].
References
1. Alahiotis S. N.: Adaptation of Drosophila enzymes to
temperature. 4. Natural selection at the alcohol
dehydrogenase locus. Genetica 59: 81-87 (1982)
References
171
2. Alber T.: Mutational effects on protein stability.
Annual Rev. Biochem. 58: 765-798 (1989)
3. de Albuquerque C. M. R. and Napp M.: Genetic
variability at the esterase-6 locus in natural populations of Drosophila simulans in relation to environmental heterogeneity. Genetics 98: 399-407 (1981)
4. Alonso S. et al.: Comparison of three actin-coding
sequences in the monuse: evolutionary relationships
between the actin genes of wann-blooded vertebrates. J. mol. Evol. 23: 11-22 (1986)
5. Altruda E et al.: The primary structure of human
hemopexin deduced from cDNA sequence: evidence
for internal repeating homology. Nucleic Acids Res.
13: 3841-59 (1985)
6. Altschul S. E and Lipman D. J.: Protein database
searches for multiple alignments. Proc. Nat. Acad.
Sci. USA 87: 5509-13 (1990)
7. Anderson P. R. and Oakeshott J. G.: Parallel geographical patterns of allozyme variation in two sibling
Drosophila species. Nature 308: 729-730 (1984)
8. Anderson S. M. and McDonald J. E: Effect of environmental alcohol on in vivo properties of Drosophila
alcohol dehydrogenase. Biochem. Genetics 19:
421-430 (1981)
9. Aquadro C. E and Avise J. c.: An assessment of
"hidden" heterogeneity within electromorphs at three
enzyme loci in deer mice. Genetics 102: 269-283
(1982)
10. Arcari P., Martinelli R. and Salvatore E: Human
glyceraldehyde-3-phosphate dehydrogenase pdeudogenes: Molecular evolution and possible mechanisms
for amplification. Biochem. Genet. 27: 439-450
(1989)
11. Argos P.: Sensitive procedure to compare amino acid
sequences. J. mol. BioI. 193: 385-396 (1987)
12. Aspinwall N.: Genetic analysis of North American
popUlations of the pink salmon, Oncorhynchnus
gorbnuscha, possible evidence for the neutral
mutation-random drift hypothesis. Evolution 28:
295-305 (1974)
13. Atchison M. and Adesnik M.: Gene conversion in a
cytochrom P-450 gene family. Proc. Nat. Acad. Sci.
USA 83: 2300-04 (1986)
14. Avise J. C.: Is evolution gradual or rectangular?
Evidence from living fishes. Proc. Nat. Acad. Sci.
USA 74: 5083-87 (1977)
15. Avise J. C. and Aquadro C. E: A comparative summary of genetic distances in the vertebrates. In:
Evolutionary Biology Vol. 15, pp. 151-185. Plenum,
New York 1982
16. Ayala E J.: Genetic differentiation during the speziation process. In: Evolutionary Biology Vol. 8, pp.
1-78. Plenum, New York 1975
17. Ayala E J.: Genetic polymorphism: from electrophoresis to DNA sequences. Experientia 39: 813-823
(1983)
18. Barnes P. T. and Laurie-Alllberg C. c.: Genetiv variability of flight muscle metabolism in Drosophila
melanogaster. III. Effects of Gpdh allozymes and
environmental temperature on power output. Genetics 112: 267-294 (1986)
19. Baroin A. et al.: Partial phylogeny of the unicellular
eukaryotes based on rapid sequencing of a portion of
28S ribosomal RNA. Proc. Nat. Acad. Sci. USA 85:
3474-78 (1988)
made up of repetive structures that are low in
information and coded by many genes, and the
conchiolins, which are a mixture of proteins of
poorly defined structure [310]. The frozen specimen of mammoth (Mammuthus primigneius) ,
found in Siberia in 1977-1979, presented a unique
opportunity for biochemical studies on an animal
species which became extinct thousands of years
ago. Particularly interesting was the completely
preserved baby mammoth "Dima", whose age
was determined as 40000 years using 14·C dating.
However, the planned DNA analysis turned out
to be unavoidably difficult. Fossil DNAs disintegrate through ageing processes into fragments
of a few hundred base pairs; become heavily
altered chemically by loss of bases, oxidation of
pyrimidines and the growth of cross-links; and
are often contaminated with foreign DNA. Only
the polymerase chain reaction (PCR) , which
facilitates sequencing starting from minute
amounts of DNA, was able to provide molecular
evidence for the close relationship of the mammoth to the present elephant species [310]. It was
much easier to examine museum materials from
more recently extinct species. Steller's sea cow
(Hydrodamalis gigas) was discovered in 1741 on
the coast of the Komandor Islands off Kamchatka
and was already extinct by 1768. Immunological
comparisons of albumins extracted from bone
with those from the fourliving sirenians show that
Hydrodamalis separated 4-8 million years ago
from its nearest relative, Dugong dugong of the
Indo-Pacific, whilst the three manatee species of
the genus Trichechus split off 17-20 million years
ago [339]. The quagga was once the most abundant zebra species in Africa; the last specimen died
in captivity in 1883. Until recently, it was not clear
whether the quagga should be considered a separate zebra species or the southern type of Equus
burchelli. Proteins extracted from quagga skin in
fact showed much more similarity to plasma proteins of E. burchelli than to the other two zebra
species, E. zebra and E. grevyi [252]. Whereas
partial sequences of quagga and E. burchelli
mtDNA are identical, those of the horse E. cabalIus contained 11 synonymous substitutions [172].
References
1. Alahiotis S. N.: Adaptation of Drosophila enzymes to
temperature. 4. Natural selection at the alcohol
dehydrogenase locus. Genetica 59: 81-87 (1982)
References
171
2. Alber T.: Mutational effects on protein stability.
Annual Rev. Biochem. 58: 765-798 (1989)
3. de Albuquerque C. M. R. and Napp M.: Genetic
variability at the esterase-6 locus in natural populations of Drosophila simulans in relation to environmental heterogeneity. Genetics 98: 399-407 (1981)
4. Alonso S. et al.: Comparison of three actin-coding
sequences in the monuse: evolutionary relationships
between the actin genes of wann-blooded vertebrates. J. mol. Evol. 23: 11-22 (1986)
5. Altruda E et al.: The primary structure of human
hemopexin deduced from cDNA sequence: evidence
for internal repeating homology. Nucleic Acids Res.
13: 3841-59 (1985)
6. Altschul S. E and Lipman D. J.: Protein database
searches for multiple alignments. Proc. Nat. Acad.
Sci. USA 87: 5509-13 (1990)
7. Anderson P. R. and Oakeshott J. G.: Parallel geographical patterns of allozyme variation in two sibling
Drosophila species. Nature 308: 729-730 (1984)
8. Anderson S. M. and McDonald J. E: Effect of environmental alcohol on in vivo properties of Drosophila
alcohol dehydrogenase. Biochem. Genetics 19:
421-430 (1981)
9. Aquadro C. E and Avise J. c.: An assessment of
"hidden" heterogeneity within electromorphs at three
enzyme loci in deer mice. Genetics 102: 269-283
(1982)
10. Arcari P., Martinelli R. and Salvatore E: Human
glyceraldehyde-3-phosphate dehydrogenase pdeudogenes: Molecular evolution and possible mechanisms
for amplification. Biochem. Genet. 27: 439-450
(1989)
11. Argos P.: Sensitive procedure to compare amino acid
sequences. J. mol. BioI. 193: 385-396 (1987)
12. Aspinwall N.: Genetic analysis of North American
popUlations of the pink salmon, Oncorhynchnus
gorbnuscha, possible evidence for the neutral
mutation-random drift hypothesis. Evolution 28:
295-305 (1974)
13. Atchison M. and Adesnik M.: Gene conversion in a
cytochrom P-450 gene family. Proc. Nat. Acad. Sci.
USA 83: 2300-04 (1986)
14. Avise J. C.: Is evolution gradual or rectangular?
Evidence from living fishes. Proc. Nat. Acad. Sci.
USA 74: 5083-87 (1977)
15. Avise J. C. and Aquadro C. E: A comparative summary of genetic distances in the vertebrates. In:
Evolutionary Biology Vol. 15, pp. 151-185. Plenum,
New York 1982
16. Ayala E J.: Genetic differentiation during the speziation process. In: Evolutionary Biology Vol. 8, pp.
1-78. Plenum, New York 1975
17. Ayala E J.: Genetic polymorphism: from electrophoresis to DNA sequences. Experientia 39: 813-823
(1983)
18. Barnes P. T. and Laurie-Alllberg C. c.: Genetiv variability of flight muscle metabolism in Drosophila
melanogaster. III. Effects of Gpdh allozymes and
environmental temperature on power output. Genetics 112: 267-294 (1986)
19. Baroin A. et al.: Partial phylogeny of the unicellular
eukaryotes based on rapid sequencing of a portion of
28S ribosomal RNA. Proc. Nat. Acad. Sci. USA 85:
3474-78 (1988)