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Full-Text Articles in Biology

Rad51-Mediated Interhomolog Recombination During Budding Yeast Meiosis Is Promoted By The Meiotic Recombination Checkpoint And The Conserved Pif1 Helicase, Andrew Ziesel, Qixuan Weng, Jasvinder S. Ahuja, Abhishek Bhattacharya, Raunak Dutta, Evan Cheng, G. Valentin Borner Ph.D., Michael Lichten, Nancy M. Hollingsworth Dec 2022

Rad51-Mediated Interhomolog Recombination During Budding Yeast Meiosis Is Promoted By The Meiotic Recombination Checkpoint And The Conserved Pif1 Helicase, Andrew Ziesel, Qixuan Weng, Jasvinder S. Ahuja, Abhishek Bhattacharya, Raunak Dutta, Evan Cheng, G. Valentin Borner Ph.D., Michael Lichten, Nancy M. Hollingsworth

Biological, Geological, and Environmental Faculty Publications

During meiosis, recombination between homologous chromosomes (homologs) generates crossovers that promote proper segregation at the first meiotic division. Recombination is initiated by Spo11-catalyzed DNA double strand breaks (DSBs). 5' end resection of the DSBs creates 3' single strand tails that two recombinases, Rad51 and Dmc1, bind to form presynaptic filaments that search for homology, mediate strand invasion and generate displacement loops (D-loops). D-loop processing then forms crossover and noncrossover recombinants. Meiotic recombination occurs in two temporally distinct phases. During Phase 1, Rad51 is inhibited and Dmc1 mediates the interhomolog recombination that promotes homolog synapsis. In Phase 2, Rad51 becomes active …


Combining Paternally And Maternally Inherited Mitochondrial Dna For Analysis Of Population Structure In Mussels, Robert A. Krebs Jun 2004

Combining Paternally And Maternally Inherited Mitochondrial Dna For Analysis Of Population Structure In Mussels, Robert A. Krebs

Biological, Geological, and Environmental Faculty Publications

Sequence divergence for a fragment of the 16S rRNA gene was compared to identify the advantages in using mitochondrial genes that descend separately through the female and male lineages to examine population structure. The test compared divergence among four local species of freshwater mussels (Unionidae) and was extended to multiple populations of one species, Pyganodon grandis. For the same gene, the male-inherited sequences diverged at a faster rate, producing longer branch lengths in the phylogenies. Of particular use were sequences extracted from P. grandis populations from the southern region of the Lake Erie watershed (Ohio, USA); five male-inherited haplotypes were …


An Analysis Of Diversity In Freshwater Mussels (Bivalvia: Unionidae) Of The Cuyahoga And Rocky River Watersheds (Ohio, Usa) Based On The 16s Rrna Gene, Robert A. Krebs, Roxana N. Vlasceanu, Michael J.S. Tevesz Jan 2003

An Analysis Of Diversity In Freshwater Mussels (Bivalvia: Unionidae) Of The Cuyahoga And Rocky River Watersheds (Ohio, Usa) Based On The 16s Rrna Gene, Robert A. Krebs, Roxana N. Vlasceanu, Michael J.S. Tevesz

Biological, Geological, and Environmental Faculty Publications

The continued loss of freshwater unionid mussel species in the Great Lakes region, and particularly from Lake Erie, raises the question of how much phylogenetic and genetic variation remain in the watershed. The introduction of molecular markers into population biology offers one reproducible technique for assessing this variation. A fragment of the 16S rRNA gene of mitochondrial DNA has previously been used to infer phylogenetic relationships in the family Unionidae. Therefore, we reanalyzed these published molecular data with the addition of 12 species from the Cuyahoga and Rocky rivers in northeast Ohio. Both rivers drain to Lake Erie. The species …


Heritability Of Expression Of The 70kd Heat-Shock Protein In Drosophila Melanogaster And Its Relevance To The Evolution Of Thermotolerance, Robert A. Krebs, Martin E. Feder, Jeehyun Lee Jun 1998

Heritability Of Expression Of The 70kd Heat-Shock Protein In Drosophila Melanogaster And Its Relevance To The Evolution Of Thermotolerance, Robert A. Krebs, Martin E. Feder, Jeehyun Lee

Biological, Geological, and Environmental Faculty Publications

The principle inducible heat-shock protein of Drosophila melanogasrer, Hsp70, contributes to thermotolerance throughout the entire life cycle of the species but may also reduce fitness in some life stages. In principle, selection might maximize the benefits of Hsp70 expression relative to its costs by adjusting the magnitude of Hsp70 expression for each life-cycle stage independently. Therefore we examined whether the magnitude of Hsp70 ex pre sion varied during the life cycle and the relationship of this variation to several life-history traits. For 28 isofemale lines derived from a single natural population, estimates of heritable variation in Hsp70 expression ranged between …