Black Bengal goat is the heritage and one of the potential genetic resources of Bangladesh. Genetic and phenotypic parameters for semen characteristics and their relationships with scrotal circumference in Black Bengal bucks were estimated in this experiment. Genetic parameters were estimated by residual maximum likelihood procedure, fitting an animal model ignoring maternal genetic or permanen...

When ejaculates from rival males compete for fertilization, there is strong selection for sperm traits that enhance fertilization success. Sperm quantity is one such trait, and numerous studies have demonstrated a positive association between sperm competition and both testes size and the number of sperm available for copulations. Sperm competition is also thought to favor increases in sperm qu...

Postcopulatory sexual selection favours males which are strong offensive and defensive sperm competitors. As a means of identifying component traits comprising each strategy, we used an experimental evolution approach. Separate populations of Drosophila melanogaster were selected for enhanced sperm offence and defence. Despite using a large outbred population and evidence of substantive genetic...

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 ...

All birds studied thus far are able to store spermatozoa within their oviducts for periods that can vary from several days to weeks, depending upon the species. Turkeys have a relatively long storage period compared with chickens, an observation that leads to the suggestion that sperm residing within the oviduct may interact with sperm entering the oviduct from later inseminations. Multiple sou...

A swimming sperm cell appears to perfectly capture the individualist Darwinian struggle, as it frantically races onwards towards a waiting egg. Consistent with this imagery, sperm morphology and behaviour in many organisms appears exquisitely designed to maximise the chances of fertilisation of each individual sperm cell [1]. However, there are numerous less obliging cases where sperm seem poor...

Sperm-specific natural selection Sperm cells are genetically haploid, but because of the cytoplasmic bridges that link cells, they can be transcriptionally diploid. However, some gene transcripts not shared. Bhutani et al. sequenced single sperm from mice, cattle, and macaques to determine extent distortion in expression these putatively selfish transcripts, which authors call genoinformative m...

Male factors leading to infertility account for at least half of all cases of infertility worldwide. The purpose of this review is to highlight the importance of sperm DNA integrity. A systematic literature search was performed up to January 2015 in order to determine the impact of sperm DNA integrity and of the techniques used to determine it. Only articles presenting sperm aneuploidy together...

STUDY QUESTION Is the presence of nuclear vacuoles really a negative parameter? SUMMARY ANSWER As sperm vacuoles are associated with acrosomal and capacitation status, they appear to be a reflection of normal sperm physiology. WHAT IS KNOWN ALREADY The selection of sperm under a high magnification has been proposed as a strategy to increase the success rates of ICSI, through a better select...

What is sperm storage? Sperm storage is most commonly defined as the maintenance of sperm inside a female’s reproductive tract for an extended period of time. Because the fate of sperm post-copulation is important for understanding sexual selection, sperm storage is a particularly interesting characteristic that may have drastic impacts on the operation of post-copulatory sexual selection. Sper...