Biomaterial Database

Molecular variation at the vermilion locus in geographically diverse populations of Drosophila melanogaster and D. simulans. 1995

D J Begun, and C F Aquadro

Section of Genetics and Development, Cornell University, Ithaca, New York 14853, USA.

We surveyed nucleotide variation at vermilion in population samples of Drosophila melanogaster from Africa, Asia and the Americas to test the hypothesis that the vermilion gene was a target of balancing selection and to improve our understanding of geographic differentiation. Patterns of polymorphism and divergence showed no evidence for non-neutral evolution. However, the frequency spectrum of polymorphic sites in some non-African samples departed from the neutral equilibrium expectation. Furthermore, there were high levels of linkage disequilibrium in non-African samples, despite apparently high rates of crossing over in the vermilion region. In the absence of comparable data from other loci in these same population samples, we cannot determine whether the unusual patterns of variation at vermilion reflect demographic as opposed to locus-specific events. We found surprisingly high levels of differentiation at vermilion between U.S. and Congo samples of D. simulans. In light of previously published allozyme and mtDNA data that provided no evidence for significant differentiation between African and non-African D. simulans populations, the vermilion data raise the possibility that both mtDNA and allozymes have been influenced by selection.

UI	MeSH Term	Description	Entries
D007438	Introns	Sequences of DNA in the genes that are located between the EXONS. They are transcribed along with the exons but are removed from the primary gene transcript by RNA SPLICING to leave mature RNA. Some introns code for separate genes.	Intervening Sequences,Sequences, Intervening,Intervening Sequence,Intron,Sequence, Intervening
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
D009656	North America	The northern continent of the Western Hemisphere, extending northward from the Colombia-Panama border and including CENTRAL AMERICA, MEXICO, Caribbean area, the UNITED STATES, CANADA and GREENLAND. The term often refers more narrowly to MEXICO, continental UNITED STATES, AND CANADA.	Northern America
D011110	Polymorphism, Genetic	The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.	Gene Polymorphism,Genetic Polymorphism,Polymorphism (Genetics),Genetic Polymorphisms,Gene Polymorphisms,Polymorphism, Gene,Polymorphisms (Genetics),Polymorphisms, Gene,Polymorphisms, Genetic
D003434	Crossing Over, Genetic	The reciprocal exchange of segments at corresponding positions along pairs of homologous CHROMOSOMES by symmetrical breakage and crosswise rejoining forming cross-over sites (HOLLIDAY JUNCTIONS) that are resolved during CHROMOSOME SEGREGATION. Crossing-over typically occurs during MEIOSIS but it may also occur in the absence of meiosis, for example, with bacterial chromosomes, organelle chromosomes, or somatic cell nuclear chromosomes.	Crossing Over,Crossing-Over, Genetic,Crossing Overs,Genetic Crossing Over,Genetic Crossing-Over
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
D005091	Exons	The parts of a transcript of a split GENE remaining after the INTRONS are removed. They are spliced together to become a MESSENGER RNA or other functional RNA.	Mini-Exon,Exon,Mini Exon,Mini-Exons
D005787	Gene Frequency	The proportion of one particular in the total of all ALLELES for one genetic locus in a breeding POPULATION.	Allele Frequency,Genetic Equilibrium,Equilibrium, Genetic,Allele Frequencies,Frequencies, Allele,Frequencies, Gene,Frequency, Allele,Frequency, Gene,Gene Frequencies
D005843	Geography	The science dealing with the earth and its life, especially the description of land, sea, and air and the distribution of plant and animal life, including humanity and human industries with reference to the mutual relations of these elements. (From Webster, 3d ed)	Factor, Geographic,Factors, Geographic,Geographic Factor,Geographic Factors,Geography, Human,Human Geography