Nucleotide sequences of immunoglobulin eta genes of chimpanzee and orangutan: DNA molecular clock and hominoid evolution
To determine the phylogenetic relationships among hominoids and the dates of their divergence, the complete nucleotide sequences of the constant region of the immunoglobulin eta-chain (C/sub eta1/) genes from chimpanzee and orangutan have been determined. These sequences were compared with the human eta-chain constant-region sequence. A molecular clock (silent molecular clock), measured by the degree of sequence divergence at the synonymous (silent) positions of protein-encoding regions, was introduced for the present study. From the comparison of nucleotide sequences of ..cap alpha../sub 1/-antitrypsin and ..beta..- and delta-globulin genes between humans and Old World monkeys, the silent molecular clock was calibrated: the mean evolutionary rate of silent substitution was determined to be 1.56 x 10/sup -9/ substitutions per site per year. Using the silent molecular clock, the mean divergence dates of chimpanzee and orangutan from the human lineage were estimated as 6.4 +/- 2.6 million years and 17.3 +/- 4.5 million years, respectively. It was also shown that the evolutionary rate of primate genes is considerably slower than those of other mammalian genes.
- Research Organization:
- Osaka Univ. School of Medicine, Japan
- OSTI ID:
- 5722760
- Journal Information:
- Proc. Natl. Acad. Sci. U.S.A.; (United States), Vol. 84:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
IMMUNOGLOBULINS
DNA SEQUENCING
PRIMATES
BIOLOGICAL EVOLUTION
DNA
GENETIC MAPPING
MAN
NUCLEOTIDES
PHOSPHORUS 32
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
DAYS LIVING RADIOISOTOPES
GLOBULINS
ISOTOPES
LIGHT NUCLEI
MAMMALS
MAPPING
NUCLEI
NUCLEIC ACIDS
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
PHOSPHORUS ISOTOPES
PROTEINS
RADIOISOTOPES
STRUCTURAL CHEMICAL ANALYSIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques