نتایج جستجو برای: sexual reproduction

تعداد نتایج: 177469  

2013
Marianna Feretzaki Joseph Heitman

Cryptococcus neoformans is a human fungal pathogen with a defined sexual cycle. Nutrient-limiting conditions and pheromones induce a dimorphic transition from unicellular yeast to multicellular hyphae and the production of infectious spores. Sexual reproduction involves cells of either opposite (bisexual) or one (unisexual) mating type. Bisexual and unisexual reproduction are governed by shared...

Journal: :Phytopathology 2000
J Zhan C C Mundt B A McDonald

ABSTRACT We find that the maximum likelihood method proposed by J. K. M. Brown has deficiencies that limit its usefulness for actual data sets. We propose two alternative statistical methods based on maximum likelihood that could be used to quantify rates of recombination and immigration in fungal populations. We also show that minor modification of our original method, which was based upon pos...

2016
YuSong Cao Yian Xiao Haiqun Huang Jiancheng Xu Wenhai Hu Ning Wang

Climate warming can shift the reproductive phenology of plant, and hence dramatically reduced the reproductive capacity both of density-dependent and -independent plant species. But it is still unclear how climate warming affects flowering phenology and reproductive allocation of plant under different planting densities. Here, we assessed the impact of simulated warming on flowering phenology a...

Journal: :Current Biology 2009
Kayla C. King Lynda F. Delph Jukka Jokela Curtis M. Lively

The maintenance of sexual reproduction in natural populations is a pressing question for evolutionary biologists. Under the "Red Queen" hypothesis, coevolving parasites reduce the reproductive advantage of asexual reproduction by adapting to infect clonal genotypes after they become locally common. In addition, the "geographic mosaic" theory of coevolution proposes that structured populations o...

Journal: :Journal of embryology and experimental morphology 1971
C Vowinckel J R Marsden

Five successive generations of asexually derived populations of D. tigrina and their sexually derived parental population were reared under each of six combinations of 20, 23 and 26 °C with 12 and 16 h of daylight. Asexual and sexual reproduction were recorded for each population. Peaks of asexual reproduction occurred increasingly earlier in consecutive generations to finally disappear or occu...

Journal: :Proceedings. Biological sciences 2008
Mark Vellend Isabelle Litrico

Organisms ranging from bacteria and corals to plants and vertebrates can form intransitive competitive networks, in which coexistence can be maintained because no one species or genotype is superior to all others. However, in the simplest case with three competing types, the long-term outcome may not be so clear if two of the three represent the ends of a continuous heritable trait distribution...

Journal: :Journal of theoretical biology 2001
T Flatt N Maire M Doebeli

To date, only a few studies have focused on the effects of sex on population dynamics. Previous models have typically found that sexual reproduction dampens population fluctuations. Although asexual and sexual reproduction are just the two endpoints along a continuum of varying rates of sex, previous work has ignored the effects of intermediate degrees of sex on population dynamics. Here we stu...

Journal: :BioEssays : news and reviews in molecular, cellular and developmental biology 2011
Tom Wenseleers Annette Van Oystaeyen

The study of alternative genetic systems and mixed modes of reproduction, whereby sexual and asexual reproduction is combined within the same lifecycle, is of fundamental importance as they may shed light on classical evolutionary issues, such as the paradox of sex. Recently, several such cases were discovered in social insects. A closer examination of these systems has revealed many amazing fa...

2015
Tomer Avidor-Reiss Atul Khire Emily L. Fishman Kyoung H. Jo

Centrioles are conserved, self-replicating, microtubule-based, 9-fold symmetric subcellular organelles that are essential for proper cell division and function. Most cells have two centrioles and maintaining this number of centrioles is important for animal development and physiology. However, how animals gain their first two centrioles during reproduction is only partially understood. It is we...

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