Search results for "sperma"
showing 10 items of 296 documents
Postcopulatory sexual selection generates speciation phenotypes in Drosophila.
2013
Background: Identifying traits that reproductively isolate species and the selective forces underlying their divergence is a central goal of evolutionary biology and speciation research. There is growing recognition that postcopulatory sexual selection which can drive rapid diversification of interacting ejaculate and female reproductive tract traits that mediate sperm competition may be an engine of speciation. Conspecific sperm precedence (CSP) is a taxonomically widespread form of reproductive isolation but the selective causes and divergent traits responsible for CSP are poorly understood. Results: To test the hypothesis that postcopulatory sexual selection can generate reproductive iso…
The evolution of sperm morphometry in pheasants
2007
7 pages; International audience; Post-copulatory sexual selection is thought to be a potent evolutionary force driving the diversification of sperm shape and function across species. In birds, insemination and fertilization are separated in time and sperm storage increases the duration of sperm-female interaction and hence the opportunity for sperm competition and cryptic female choice. We performed a comparative study of 24 pheasant species (Phasianidae, Galliformes) to establish the relative importance of sperm competition and the duration of sperm storage for the evolution of sperm morphometry (i.e. size of different sperm traits). We found that sperm size traits were negatively associat…
Synthetic cartography for mapping biodiversity in the Mediterranean region: Sicily as a case study
2018
This paper proposes a new hierarchical land classification system for the mapping of species distribution at national or regional scales. Our integrative framework incorporates two hierarchical levels inferred from historical, climatic, geomorphological and geological attributes. The feasibility of this proposal is based on the use of historical collections and literature data, as well as on its ability to combine old low-precision data with more recent records of higher resolution. The system is set up for vascular plants, but it can also be used for other taxonomic groups. Furthermore, it has the potential for application to the whole Mediterranean region because it is based on informatio…
Megymenum tuberculatum, a new species of Megymenini from Java and a review of distribution of M. brevicorne (Hemiptera: Heteroptera: Dinidoridae)
2020
Megymenum tuberculatum Hemala & Kocorek, sp. nov. (Hemiptera: Heteroptera: Dinidoridae: Megymeninae: Megymenini) from Java (Indonesia) is described, illustrated and compared with M. brevicorne (Fabricius, 1787). Although the description is based on only one female specimen, the differences in the morphology of head, pronotum, and spermatheca are significant. In addition, M. brevicorne is briefly redescribed and its distribution and biology reviewed along with its first record from Nepal.
Quantitative Genetics of the Aging of Reproductive Traits in the Houbara Bustard
2015
International audience; Do all traits within an organism age for the same reason? Evolutionary theories of aging share a common assumption: the strength of natural selection declines with age. A corollary is that additive genetic variance should increase with age. However, not all senescent traits display such increases suggesting that other mechanisms may be at play. Using longitudinal data collected from more than 5400 houbara bustards (Chlamydotis undulata) with an exhaustive recorded pedigree, we investigated the genetics of aging in one female reproductive trait (egg production) and three male reproductive traits (courtship display rate, ejaculate size and sperm viability), that displa…
Morphology of spermatheca in Scutelleridae (Hemiptera: Pentatomoidea) and its taxonomic significance
2016
AbstractStructures of spermatheca in 63 species of Scutelleridae (Hemiptera) representing 46 genera and all subfamilies currently recognised in the family were examined and compared. The morphology of three main parts of the spermatheca (receptacle, intermediate part, and spermathecal duct) was described and three main types of spermatheca in Scutelleridae were identified. The taxonomic importance of spermathecal features for the higher classification of scutellerids is discussed.
What the human sperm methylome tells us.
2017
Aim: To characterize the sperm methylome in semen samples from 19 donors with proven fertility. Materials & methods: Bisulfite-converted sperm DNA was hybridized on the HumanMethylation450 Infinium BeadChip platform. CpG fluorescence intensities were extracted and converted to β-values. Results: The sperm methylome is highly homogeneous and hypomethylated. Genes with hypomethylated promoters are ontologically associated to biological functions related to spermatogenesis and embryogenesis. Sex chromosomes are the most hypomethylated chromosomes, supporting data that indicated their essential role in spermatogenesis. A total of 94 genes are resistant to demethylation, being strong candid…
Sperm DNA fragmentation: An early and reliable marker of air pollution.
2017
Environmental factors could have a key role in the continuous and remarkable decline of sperm quality observed in the last decades. This study compared the seminal parameters and sperm DFI in men living in areas with different levels of air pollution. Results demonstrate that both steel plants workers and patients living in a high polluted area show a mean percentage of sperm DNA fragmentation above 30%, highlighting a clear sperm damage. In this work, two different techniques were used to measure sperm DNA damage in patientsâ groups, finding in both cases a high sperm DFI in patients living in polluted areas. We candidate sperm DNA fragmentation as a valuable early marker of the presence…
Morphometric and kinematic sperm subpopulations in split ejaculates of normozoospermic men
2016
This study was designed to analyze the sperm kinematic and morphometric subpopulations in the different fractions of the ejaculate in normozoospermic men. Ejaculates from eight normozoospermic men were collected by masturbation in three fractions after 3-5 days of sexual abstinence. Analyses of sperm motility by computer-assisted sperm analysis (CASA-Mot), and of sperm morphometry by computer-assisted sperm morphometry analysis (CASA-Morph) using fluorescence were performed. Clustering and discriminant procedures were performed to identify sperm subpopulations in the kinematic and morphometric data obtained. Clustering procedures resulted in the classification of spermatozoa into three kine…
Old meets new: Comparative examination of conventional and innovative RNA-based methods for body fluid identification of laundered seminal fluid stai…
2018
Abstract The knowledge about the type of the body fluid/tissue that contributed to a trace can provide contextual insight into crime scene reconstruction and connect a suspect or a victim to a crime scene. Especially in sexual assault cases, it is important to verify the presence of spermatozoa. Victims often tend to clean their underwear/bedding after a sexual assault. If they later decide to report the crime to the police, in our experience, investigators usually do not send laundered items for DNA examination, since they believe that analysis after washing is no longer promising. As not only the individualization of traces on laundered items could be important in court, but also the type…