نتایج جستجو برای: gamete biology

تعداد نتایج: 165412  

Journal: :Human Reproduction 1996

Journal: :Biology of Reproduction 1992

Journal: :Zoology and ecology 2023

The striped snakehead Channa striata is a valuable food fish and has high market value. feeding natural breeding grounds of this economically important species have been reduced due to increasing anthropogenic activities habitat alterations in the Gangetic River system. present study was undertaken assess reproductive biology C. striata, which widely distributed India many other Asian countries...

Journal: :Proceedings. Biological sciences 2014
Geoff A Parker Jussi Lehtonen

Both gamete competition and gamete limitation can generate anisogamy from ancestral isogamy, and both sperm competition (SC) and sperm limitation (SL) can increase sperm numbers. Here, we compare the marginal benefits due to these two components at any given population level of sperm production using the risk and intensity models in sperm economics. We show quite generally for the intensity mod...

Journal: :Proceedings. Biological sciences 2002
Rhonda R Snook Therese Ann Markow

Gamete production for both males and females can be energetically expensive such that selection should maximize fertilization opportunities while minimizing fertilization costs. In laboratory studies of Drosophila reproduction, however, the failure of eggs to yield adult progeny can be quite high, suggesting that female control over gamete utilization is surprisingly inefficient. We examined ga...

Journal: :Current Biology 2014
Thomas Dresselhaus William J. Snell

During fertilization in eukaryotes, gametes of the opposite sex undergo a complex series of interactions that culminate in cell fusion. A new study on gamete interaction in plants has identified the first protein in multicellular organisms shown by gene disruption to be essential for gamete membrane adhesion.

2017
Houssem Rouiss José Cuenca Luis Navarro Patrick Ollitrault Pablo Aleza

Unreduced (2n) gametes have played a pivotal role in polyploid plant evolution and are useful for sexual polyploid breeding in various species, particularly for developing new seedless citrus varieties. The underlying mechanisms of 2n gamete formation were recently revealed for Citrus reticulata but remain poorly understood for other citrus species, including lemon (C. limon [L.] Burm. f.). Her...

Journal: :Human reproduction 2008
A Skoog Svanberg G Sydsjö K Ekholm Selling C Lampic

BACKGROUND Assisted reproductive technology (ART) legislation in Sweden has undergone a gradual transformation from being fairly restrictive when first introduced to becoming more permissive in recent years. Regarding gamete donation, Sweden became the first country to pass legislation about disclosure by establishing a child's right to find out the identity of the gamete donor once the child h...

Journal: :The Biological bulletin 1991
D R Levitan

Gamete production and fertilization influence zygote production. While gamete production is correlated positively with body size, individual fertilization success may be a function of population density. Usually it is assumed that when high population density leads to reduced body size and gamete production, per capita zygote production is diminished. This field study of the sea urchin Diadema ...

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