Results 11 to 20 of about 158,096 (183)

Selection for longer lived sperm within ejaculate reduces reproductive ageing in offspring [PDF]

open access: yesEvolution Letters, 2019
Males produce numerous sperm in a single ejaculate that greatly outnumber their potential egg targets. Recent studies found that phenotypic and genotypic variation among sperm in a single ejaculate of a male affects the fitness and performance of the ...
Ghazal Alavioon   +4 more
doaj   +3 more sources

Intramale variation in sperm size: functional significance in a polygynous mammal [PDF]

open access: yesPeerJ, 2015
Studies concerning the relationships between sperm size and velocity at the intraspecific level are quite limited and often yielded contradictory results across the animal kingdom.
José Luis Ros-Santaella   +2 more
doaj   +4 more sources

#159 : Aneuploidy Embryos Rate in Good Prognosis Patients After Fertilization Using ICSI and IMSI Methods

open access: yesFertility & Reproduction, 2023
Background and Aims: Embryo aneuploidy is caused by many factors, including patient age, sperm quality and sperm selection method. There are several methods for selecting sperm, ICSI (intracytoplasmic sperm injection) and IMSI (intracytoplasmic ...
Reza Raharjo   +3 more
doaj   +1 more source

No evidence for pre-copulatory sexual selection on sperm length in a passerine bird. [PDF]

open access: yesPLoS ONE, 2012
There is growing evidence that post-copulatory sexual selection, mediated by sperm competition, influences the evolution of sperm phenotypes. Evidence for pre-copulatory sexual selection effects on sperm traits, on the other hand, is rather scarce.
Jan T Lifjeld   +7 more
doaj   +1 more source

Sperm quality metrics were improved by a biomimetic microfluidic selection platform compared to swim-up methods

open access: yesMicrosystems & Nanoengineering, 2023
Sperm selection is an essential component of all assisted reproductive treatments (ARTs) and is by far the most neglected step in the ART workflow in regard to technological innovation.
Steven A. Vasilescu   +4 more
doaj   +1 more source

The birth of a healthy child in a married couple with a history of multiple unsuccessful attempts at ART by selecting sperm on oocyte-cumulus complexes. Case report [PDF]

open access: yesГинекология, 2023
In male infertility, couples must use assisted reproductive technologies with the intracytoplasmic sperm injection (ICSI) technique. A significant disadvantage of ICSI is bypassing natural selection barriers since selective processes in the female ...
Alina V. Chistyakova   +5 more
doaj   +1 more source

Sperm design and variation in the New World blackbirds (Icteridae) [PDF]

open access: yes, 2009
Post-copulatory sexual selection (PCSS) is thought to be one of the evolutionary forces responsible for the rapid and divergent evolution of sperm design. However, whereas in some taxa particular sperm traits are positively associated with PCSS, in other
AF Malo   +81 more
core   +2 more sources

The evolution of sperm morphometry in pheasants [PDF]

open access: yes, 2007
Postcopulatory sexual selection is thought to be a potent evolutionary force driving the diversification of sperm shape and function across species. In birds, insemination and fertilisation are separated in time and sperm storage increases the duration
Birkhead, T.R.   +5 more
core   +3 more sources

Postcopulatory sexual selection [PDF]

open access: yes, 2002
The female reproductive tract is where competition between the sperm of different males takes place, aided and abetted by the female herself. Intense postcopulatory sexual selection fosters inter-sexual conflict and drives rapid evolutionary change to ...
A Civetta   +132 more
core   +1 more source

Psychological and physiological adaptations to sperm competition in humans [PDF]

open access: yes, 2005
Postcopulatory competition between males, in the form of sperm competition, is a widespread phenomenon in many animal species. The extent to which sperm competition has been an important selective pressure during human evolution remains controversial ...
Goetz, AT, Pound, N, Shackelford, TK
core   +2 more sources

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