Biomaterial Database

Lack of correlation between interspecific divergence and intraspecific polymorphism at the suppressor of forked region in Drosophila melanogaster and Drosophila simulans. 1993

C H Langley, and J MacDonald, and N Miyashita, and M Aguadé

Center for Population Biology, University of California, Davis 95616.

Levels of DNA sequence polymorphism at the suppressor of forked [su(f)] region in natural populations of Drosophila melanogaster and Drosophila simulans are estimated by restriction map analysis. su(f) is located at the base of the euchromatic portion of the X chromosome where the level of crossing-over per physical length is extremely low. In a survey of 55 alleles from three natural populations of D. melanogaster, only 2 restriction sites of 27 hexanucleotide and 108 tetranucleotide restriction sites scored are polymorphic. Among 103 alleles from three natural populations of D. simulans, just one polymorphic restriction site is found in 109 tetranucleotide-recognizing restriction sites scored. The few polymorphisms in these surveys yield estimates of per site heterozygosities (0.00, 0.0002, and 0.0005, respectively) at least a factor of 10 less than the average observed at loci located in regions of the genome with normal levels of crossing-over. Because under a broad category of models of molecular evolution (including the neutral theory) a correlation between levels of polymorphism and interspecific divergence is expected, the DNA sequence divergence is examined for the su(f) region. Contrary to the predicted correlation, the estimated divergence (0.12 substitution per silent site) is, in fact, greater than that observed at loci in regions of normal crossing-over. According to an alternative hypothesis (hitchhiking effect model) intraspecific polymorphism is swept out of the population in regions of the genome closely linked to rare but selectively favored variants as they quickly go to fixation; the rate of divergence is, however, unaffected by these rare hitchhiking events. Thus, the observed paucity of polymorphism and lack of correlation with divergence are in accord with the theory of the hitchhiking effect and several recent reports of polymorphism and divergence in other genomic regions with reduced crossing-over per physical length.

UI	MeSH Term	Description	Entries
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D012150	Polymorphism, Restriction Fragment Length	Variation occurring within a species in the presence or length of DNA fragment generated by a specific endonuclease at a specific site in the genome. Such variations are generated by mutations that create or abolish recognition sites for these enzymes or change the length of the fragment.	RFLP,Restriction Fragment Length Polymorphism,RFLPs,Restriction Fragment Length Polymorphisms
D004330	Drosophila	A genus of small, two-winged flies containing approximately 900 described species. These organisms are the most extensively studied of all genera from the standpoint of genetics and cytology.	Fruit Fly, Drosophila,Drosophila Fruit Flies,Drosophila Fruit Fly,Drosophilas,Flies, Drosophila Fruit,Fly, Drosophila Fruit,Fruit Flies, Drosophila
D004331	Drosophila melanogaster	A species of fruit fly frequently used in genetics because of the large size of its chromosomes.	D. melanogaster,Drosophila melanogasters,melanogaster, Drosophila
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001483	Base Sequence	The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.	DNA Sequence,Nucleotide Sequence,RNA Sequence,DNA Sequences,Base Sequences,Nucleotide Sequences,RNA Sequences,Sequence, Base,Sequence, DNA,Sequence, Nucleotide,Sequence, RNA,Sequences, Base,Sequences, DNA,Sequences, Nucleotide,Sequences, RNA
D014960	X Chromosome	The female sex chromosome, being the differential sex chromosome carried by half the male gametes and all female gametes in human and other male-heterogametic species.	Chromosome, X,Chromosomes, X,X Chromosomes
D015183	Restriction Mapping	Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.	Endonuclease Mapping, Restriction,Enzyme Mapping, Restriction,Site Mapping, Restriction,Analysis, Restriction Enzyme,Enzyme Analysis, Restriction,Restriction Enzyme Analysis,Analyses, Restriction Enzyme,Endonuclease Mappings, Restriction,Enzyme Analyses, Restriction,Enzyme Mappings, Restriction,Mapping, Restriction,Mapping, Restriction Endonuclease,Mapping, Restriction Enzyme,Mapping, Restriction Site,Mappings, Restriction,Mappings, Restriction Endonuclease,Mappings, Restriction Enzyme,Mappings, Restriction Site,Restriction Endonuclease Mapping,Restriction Endonuclease Mappings,Restriction Enzyme Analyses,Restriction Enzyme Mapping,Restriction Enzyme Mappings,Restriction Mappings,Restriction Site Mapping,Restriction Site Mappings,Site Mappings, Restriction
D017344	Genes, Insect	The functional hereditary units of INSECTS.	Insect Genes,Gene, Insect,Insect Gene