Search results for "Lethal allele"
showing 4 items of 4 documents
Highly efficient construction of infectious viroid-derived clones
2019
[Background] Viroid research generally relies on infectious cDNA clones that consist of dimers of the entire viroid sequence. At present, those dimers are generated by self-ligation of monomeric cDNA, a strategy that presents several disadvantages: (i) low efficiency, (ii) it is a non-oriented reaction requiring tedious screenings and (iii) additional steps are required for cloning into a binary vector for agroinfiltration or for in vitro RNA production.
Genetic polymorphism and high detrimental load in natural populations of Drosophila melanogaster from cellar and vineyard
1987
Two Spanish natural populations of Drosophila melanogaster have been analysed with respect to genetic variability in third chromosome viability. The two populations, although from the same locality, belong to relatively different habitats: the inside of a cellar and a vineyard. The patterns of homozygote and heterozygote viability are similar in both populations. The homozygous detrimental loads estimated are very high and the values for the D:L (detrimental/lethal) ratio close to 2.5, which is higher than any previously found. The environmental variance of viability, average degrees of dominance of lethal genes and of viability polygenes and effective population sizes were estimated in eac…
Colonization of America by Drosophila subobscura: association between Odh gene haplotypes, lethal genes and chromosomal arrangements.
2004
The colonization of America by Drosophila subobscura has been a unique exper iment in nature that has allowed us to explore the effects of evolution on a continental scale. To analyze this evolutionary event, nucleotide sequences of the Odh (Octanol dehydrogenase) gene were obtained for 43 lethal chromosomal lines from colonizing populations of North America and 5 from South America, in addition to 5 chromosomal lines from Europe with different viabilities and 2 from laboratory marker stocks. Since 10 different Odh haplotypes were found in America, the minimum number of colonizers would be 5 (or 3 mated females). Only one Odh haplotype was found in American O(5) inversions confirming that o…
Molecular variation in the Odh gene in Chilean natural populations of Drosophila subobscura
2008
A 793-nucleotide fragment from the D. subobscura Odh gene was sequenced in 46 lethal chromosomal lines from two South American colonizing populations (18 from Santiago de Chile and 28 from Puerto Montt). Only eight different haplotypes were found and, with just one exception, all had previously been detected in North American samples. The exception probably corresponds to a genetic exchange between two American haplotypes. Our results confirm the loss in genetic variability due to the recent founder event, and the high resemblance between the two colonized hemispheres. One haplotype is entirely associated with the O5 inversion, the same association found in North America. Two different hapl…