منابع مشابه
Why do bacterial plasmids carry some genes and not others?
Previous explanations of why bacterial genes for certain "optional" traits tend to occur on plasmids rather than chromosomes are based on an outdated misunderstanding of natural selection. They also fail to explain why certain characters that are ubiquitous in some bacterial species tend to occur on plasmids. This paper shows that all major classes of traits usually associated with plasmids rat...
متن کاملPlant agricultural streptomycin formulations do not carry antibiotic resistance genes.
Streptomycin is used in plant agriculture for bacterial disease control, particularly against fire blight in pome fruit orchards. Concerns that this may increase environmental antibiotic resistance have led to bans or restrictions on use. Experience with antibiotic use in animal feeds raises the possible influence of formulation-delivered resistance genes. We demonstrate that agricultural strep...
متن کاملDo first-time breeding females imprint on their own eggs?
The egg-recognition processes underlying egg rejection are assumed to be based on an imprinting-like process (a female learning the aspect of her own eggs during her first breeding attempt). The imprinting-like process and the misimprinting costs have been the objective of many theoretical models and frequently have a leading role in papers published on brood parasitism; however, an experiment ...
متن کاملMeiosis: Mouse Eggs Do Their Anaphase Topsy-Turvy
The meiotic separation of sister chromatids in mature metaphase II mouse eggs is observed to depend initially on spindle lengthening (Anaphase B), then on microtubule shortening (Anaphase A). Having Anaphase B precede Anaphase A may be the mechanism by which mammalian eggs can generate a haploid chromosome number but without the loss of too much cytoplasm.
متن کاملDo Logical Truths Carry Information?
The paper deals with the question whether logical truth carry information. On the one hand it seems that we gain new information by drawing inferences or arriving at some theorems. On the other hand the formal accounts of information and information content which are most widely known today say that logical truth carry no information at all. The latter is shown by considering these accounts. Th...
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ژورنال
عنوان ژورنال: The Auk
سال: 1912
ISSN: 0004-8038,1938-4254
DOI: 10.2307/4071052