نتایج جستجو برای: sexual reproduction

تعداد نتایج: 177469  

2015
Andrea M. Wilson P. Markus Wilken Magriet A. van der Nest Emma T. Steenkamp Michael J. Wingfield Brenda D. Wingfield

Sexual reproduction is notoriously complex in fungi with species able to produce sexual progeny by utilizing a variety of different mechanisms. This is even more so for species employing multiple sexual strategies, which is a surprisingly common occurrence. While heterothallism is relatively well understood in terms of its physiological and molecular underpinnings, homothallism remains greatly ...

Journal: :Evolution; international journal of organic evolution 2012
Desiree E Allen Michael Lynch

Cyclical parthenogens are a valuable system in which to empirically test theoretical predictions as to the genetic consequences of sexual reproduction in natural populations, particularly if the frequency of sexual relative to asexual reproduction can be quantified. In this study, we used a series of lake populations of the cyclical parthenogen, Daphnia pulicaria, that vary consistently in thei...

Journal: :Journal of theoretical biology 2010
Robert M French

This paper presents an extension of the Red Queen Hypothesis (hereafter, RQH) that we call the Red Tooth Hypothesis (RTH). This hypothesis suggests that predator-prey relations may play a role in the maintenance of sexual reproduction in many higher animals. RTH is based on an interaction between learning on the part of predators and evolution on the part of prey. We present a simple predator-p...

Journal: :Integrative and comparative biology 2013
Matthew R Walsh

Sex and dormancy are intertwined in organisms that engage in asexual and sexual reproduction. The transition between asexual and sexual reproduction typically results in a dormant stage that provides a mechanism for persisting under harsh environmental conditions. For example, many zooplankton engage in sexual reproduction when environmental conditions deteriorate and produce resting eggs that ...

There are many claims that quantum mechanics plays a key role in the origin and/or operation of biological organisms. The mechanism of the meiosis, mitosis and gametes life cycle from the view-point of quantum for human has been represented. The quantum gates have been used to simulate these processes for the first time. The reason of several hundred sperms has been explained in the male too

Journal: :Genetics 2007
Jessica A Hill Sarah P Otto

In facultatively sexual species, lineages that reproduce asexually for a period of time can accumulate mutations that reduce their ability to undergo sexual reproduction when sex is favorable. We propagated Saccharomyces cerevisiae asexually for approximately 800 generations, after which we measured the change in sexual fitness, measured as the proportion of asci observed in sporulation medium....

Journal: :Biology letters 2006
Marcel Salathé

Sexual selection is a powerful and ubiquitous force in sexual populations. It has recently been argued that sexual selection can eliminate the twofold cost of sex even with low genomic mutation rates. By means of differential male mating success, deleterious mutations in males become more deleterious than in females, and it has been shown that sexual selection can drastically reduce the mutatio...

2003
Kerstin Holmstrom Henrik Jeldtoft Jensen

We compare the speed with which a sexual, respectively an asexual, population is able to respond to a biased selective pressure. Our model focuses on the Weismann hypothesis that the extra variation caused by crossing-over and recombination during sexual reproduction allows a sexual population to adapt faster. We find, however, that the extra variation amongst the progeny produced during sexual...

2018
Aleksandra Dańko Ralf Schaible Joanna Pijanowska Maciej J. Dańko

Budding hydromedusae have high reproductive rates due to asexual reproduction and can occur in high population densities along the coasts, specifically in tidal pools. In laboratory experiments, we investigated the effects of population density on the survival and reproductive strategies of a single clone of Eleutheria dichotoma. We found that sexual reproduction occurs with the highest rate at...

Journal: :Genetics 2011
Wioletta Czaja Karen Y Miller Bruce L Miller

Sexual reproduction is a fundamental developmental process that allows for genetic diversity through the control of zygote formation, recombination, and gametogenesis. The correct regulation of these events is paramount. Sexual reproduction in filamentous fungi, including mating strategy (self-fertilization/homothallism or outcrossing/heterothallism), is determined by the expression of mating t...

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