scholarly journals Linking sperm length and velocity: the importance of intramale variation

2010 ◽  
Vol 6 (6) ◽  
pp. 797-799 ◽  
Author(s):  
John L. Fitzpatrick ◽  
Francisco Garcia-Gonzalez ◽  
Jonathan P. Evans
Keyword(s):  
Sperm Morphology ◽  
Current Evidence ◽  
Swimming Velocity ◽  
Sperm Length ◽  
Functional Link ◽  
Form And Function ◽  
Selection For ◽  
Highly Correlated ◽  
And Function ◽  
Sperm Traits

Selection imposed through sperm competition is commonly thought to promote the evolution of longer sperm, since sperm length is assumed to be positively associated with sperm swimming velocity. Yet, the basis for this assumption remains controversial, and there is surprisingly little intraspecific evidence demonstrating such a link between sperm form and function. Here, we show that sperm length and velocity are highly correlated in the sea urchin Heliocidaris erythrogramma , but importantly we report that failure to account for within-male variation in these sperm traits can obscure this relationship. These findings, in conjunction with the mounting evidence for extremely high levels of intra-specific variance in sperm traits, suggest that a functional link between sperm morphology and velocity may be more prevalent than what current evidence suggests. Our findings also suggest that selection for faster swimming sperm may promote the evolution of longer sperm, thereby supporting recent findings from macroevolutionary studies.

scholarly journals Sperm morphology, adenosine triphosphate (ATP) concentration and swimming velocity: unexpected relationships in a passerine bird

2016 ◽  
Vol 283 (1837) ◽  
pp. 20161558 ◽  
Author(s):  
Clair Bennison ◽  
Nicola Hemmings ◽  
Lola Brookes ◽  
Jon Slate ◽  
Tim Birkhead
Keyword(s):  
Sperm Morphology ◽  
Passerine Bird ◽  
Negative Association ◽  
Swimming Velocity ◽  
Sperm Function ◽  
Sperm Length ◽  
Atp Content ◽  
Number Of Individuals ◽  
The Relationship ◽  
Sperm Traits

The relationship between sperm energetics and sperm function is poorly known, but is central to our understanding of the evolution of sperm traits. The aim of this study was to examine how sperm morphology and ATP content affect sperm swimming velocity in the zebra finch Taeniopygia guttata . We exploited the high inter-male variation in this species and created extra experimental power by increasing the number of individuals with very long or short sperm through artificial selection. We found a pronounced quadratic relationship between total sperm length and swimming velocity, with velocity increasing with length up to a point, but declining in the very longest sperm. We also found an unexpected negative association between midpiece length and ATP content: sperm with a short midpiece generally contained the highest concentration of ATP. Low intracellular ATP is therefore unlikely to explain reduced swimming velocity among the very longest sperm (which tend to have a shorter midpiece).

scholarly journals Sperm form and function: what do we know about the role of sexual selection?

Reproduction ◽  
2018 ◽  
Vol 155 (5) ◽  
pp. R229-R243 ◽  
Author(s):  
Stefan Lüpold ◽  
Scott Pitnick
Keyword(s):  
Sexual Selection ◽  
Sperm Morphology ◽  
Swimming Velocity ◽  
Secondary Sexual Traits ◽  
Form And Function ◽  
Biophysical Studies ◽  
Evolutionary Context ◽  
Sexual Selection Theory ◽  
And Function

Sperm morphological variation has attracted considerable interest and generated a wealth of predominantly descriptive studies over the past three centuries. Yet, apart from biophysical studies linking sperm morphology to swimming velocity, surprisingly little is known about the adaptive significance of sperm form and the selective processes underlying its tremendous diversification throughout the animal kingdom. Here, we first discuss the challenges of examining sperm morphology in an evolutionary context and why our understanding of it is far from complete. Then, we review empirical evidence for how sexual selection theory applies to the evolution of sperm form and function, including putative secondary sexual traits borne by sperm.

Sperm morphology, motility and fertilisation capacity in the myobatrachid frog Crinia georgiana

2010 ◽  
Vol 22 (3) ◽  
pp. 516 ◽  
Author(s):  
Martin A. Dziminski ◽  
J. D. Roberts ◽  
Leigh W. Simmons
Keyword(s):  
Male Fertility ◽  
Sperm Morphology ◽  
Negative Relationship ◽  
Tail Length ◽  
Aquatic Organisms ◽  
Sperm Head ◽  
Swimming Velocity ◽  
Male Body ◽  
Sperm Viability ◽  
Sperm Traits

Sperm traits have been found to vary between individuals within populations in a variety of taxa. Sperm motility, morphometry and viability may be expected to have important effects on male fertility, although previous studies have found varying patterns, especially in external fertilisers. In the present study, we examined the effects of sperm swimming velocity, the proportion of motile spermatozoa, sperm head and tail length and the proportion of live spermatozoa on fertilisation success in the externally fertilising myobatrachid frog Crinia georgiana using IVF techniques and by controlling sperm numbers. We found no effect of any of the sperm traits we measured on IVF success. Neither did we find any relationship between sperm morphology and sperm performance. There was a negative relationship between sperm viability and male body size, which could be a function of age or an alternative tactic of differential investment in spermatozoa by smaller-sized males using sneak tactics in multiple matings. In contrast with most externally fertilising aquatic organisms, high rates of fertilisation appear to be achieved in C. georgiana with relatively low sperm swimming speeds.

scholarly journals Selection on Sperm Count, but Not on Sperm Morphology or Velocity, in a Wild Population of Anolis Lizards

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2369
Author(s):  
Ariel F. Kahrl ◽  
Matthew C. Kustra ◽  
Aaron M. Reedy ◽  
Rachana S. Bhave ◽  
Heidi A. Seears ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Sperm Morphology ◽  
Wild Population ◽  
Sperm Count ◽  
Experimental Studies ◽  
Male Reproductive Success ◽  
Brown Anole ◽  
Postcopulatory Selection ◽  
Highly Correlated ◽  
Sperm Traits

Sperm competition is a widespread phenomenon that shapes male reproductive success. Ejaculates present many potential targets for postcopulatory selection (e.g., sperm morphology, count, and velocity), which are often highly correlated and potentially subject to complex multivariate selection. Although multivariate selection on ejaculate traits has been observed in laboratory experiments, it is unclear whether selection is similarly complex in wild populations, where individuals mate frequently over longer periods of time. We measured univariate and multivariate selection on sperm morphology, sperm count, and sperm velocity in a wild population of brown anole lizards (Anolis sagrei). We conducted a mark-recapture study with genetic parentage assignment to estimate individual reproductive success. We found significant negative directional selection and negative quadratic selection on sperm count, but we did not detect directional or quadratic selection on any other sperm traits, nor did we detect correlational selection on any trait combinations. Our results may reflect pressure on males to produce many small ejaculates and mate frequently over a six-month reproductive season. This study is the first to measure multivariate selection on sperm traits in a wild population and provides an interesting contrast to experimental studies of external fertilizers, which have found complex multivariate selection on sperm phenotypes.

scholarly journals Integrated and independent evolution of heteromorphic sperm types

2013 ◽  
Vol 280 (1769) ◽  
pp. 20131647 ◽  
Author(s):  
Allen J. Moore ◽  
Leonardo D. Bacigalupe ◽  
Rhonda R. Snook
Keyword(s):  
Reproductive Tract ◽  
Developmental Process ◽  
Functional Integration ◽  
Genetic Correlations ◽  
Female Reproductive Tract ◽  
Species Variation ◽  
Cell Type ◽  
Form And Function ◽  
And Function ◽  
Sperm Traits

Sperm are a simple cell type with few components, yet they exhibit tremendous between-species morphological variation in those components thought to reflect selection in different fertilization environments. However, within a species, sperm components are expected to be selected to be functionally integrated for optimal fertilization of eggs. Here, we take advantage of within-species variation in sperm form and function to test whether sperm components are functionally and genetically integrated both within and between sperm morphologies using a quantitative genetics approach. Drosophila pseudoobscura males produce two sperm types with different functions but which positively interact together in the same fertilization environment; the long eusperm fertilizes eggs and the short parasperm appear to protect eusperm from a hostile female reproductive tract. Our analysis found that all sperm traits were heritable, but short sperm components exhibited evolvabilities 10 times that of long sperm components. Genetic correlations indicated functional integration within, but not between, sperm morphs. These results suggest that sperm, despite sharing a common developmental process, can become developmentally and functionally non-integrated, evolving into separate modules with the potential for rapid and independent responses to selection.

scholarly journals Sperm wars and the evolution of male fertility

Reproduction ◽  
2012 ◽  
Vol 144 (5) ◽  
pp. 519-534 ◽  
Author(s):  
Leigh W Simmons ◽  
John L Fitzpatrick
Keyword(s):  
Sperm Competition ◽  
Swimming Speed ◽  
Male Fertility ◽  
Seminal Fluid ◽  
Future Research ◽  
Sperm Length ◽  
Seminal Fluid Proteins ◽  
Control Male ◽  
Form And Function ◽  
And Function

Females frequently mate with several males, whose sperm then compete to fertilize available ova. Sperm competition represents a potent selective force that is expected to shape male expenditure on the ejaculate. Here, we review empirical data that illustrate the evolutionary consequences of sperm competition. Sperm competition favors the evolution of increased testes size and sperm production. In some species, males appear capable of adjusting the number of sperm ejaculated, depending on the perceived levels of sperm competition. Selection is also expected to act on sperm form and function, although the evidence for this remains equivocal. Comparative studies suggest that sperm length and swimming speed may increase in response to selection from sperm competition. However, the mechanisms driving this pattern remain unclear. Evidence that sperm length influences sperm swimming speed is mixed and fertilization trials performed across a broad range of species demonstrate inconsistent relationships between sperm form and function. This ambiguity may in part reflect the important role that seminal fluid proteins (sfps) play in affecting sperm function. There is good evidence that sfps are subject to selection from sperm competition, and recent work is pointing to an ability of males to adjust their seminal fluid chemistry in response to sperm competition from rival males. We argue that future research must consider sperm and seminal fluid components of the ejaculate as a functional unity. Research at the genomic level will identify the genes that ultimately control male fertility.

Scanning tunneling microscopy (STM) of DNA and RNA

1989 ◽  
Vol 47 ◽  
pp. 34-35
Author(s):  
Patricia G. Arscott ◽  
Gil Lee ◽  
Victor A. Bloomfield ◽  
D. Fennell Evans
Keyword(s):  
Molecular Structures ◽  
Inorganic Materials ◽  
Resolving Power ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Form And Function ◽  
Dna And Rna ◽  
Calf Thymus ◽  
And Function ◽  
The Relationship

STM is one of the most promising techniques available for visualizing the fine details of biomolecular structure. It has been used to map the surface topography of inorganic materials in atomic dimensions, and thus has the resolving power not only to determine the conformation of small molecules but to distinguish site-specific features within a molecule. That level of detail is of critical importance in understanding the relationship between form and function in biological systems. The size, shape, and accessibility of molecular structures can be determined much more accurately by STM than by electron microscopy since no staining, shadowing or labeling with heavy metals is required, and there is no exposure to damaging radiation by electrons. Crystallography and most other physical techniques do not give information about individual molecules.We have obtained striking images of DNA and RNA, using calf thymus DNA and two synthetic polynucleotides, poly(dG-me5dC)·poly(dG-me5dC) and poly(rA)·poly(rU).

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