Computer simulations are used to evaluate maximum likelihood methods for inferring male fertility in plant populations. The maximum likelihood method can provide substantial power to characterize male fertilities at the population level. Results emphasize, however, the importance of adequate experimental design and evaluation of fertility estimates, as well as limitations to inference (e.g., ab...

BACKGROUND Research on fertility differentials between eastern and western Germany after German reunification in 1990 has focused on the fertility of women. Trends in the fertility of men are rarely studied due to data constraints and methodological challenges. OBJECTIVE This paper aims to close this gap by analyzing fertility differentials between eastern and western German males over the peri...

If genetic variation for fitness traits in natural populations ("standing" variation) is maintained by recurrent mutation, then quantitative-genetic properties of standing variation should resemble those of newly arisen mutations. One well-known property of standing variation for fitness traits is inbreeding depression, with its converse of heterosis or hybrid vigor. We measured heterosis for t...

Three cytoplasmic-nuclear male-sterile (CMS) lines, one each derived from Cajanus sericeus (A(1) cytoplasm), Cajanus scarabaeoides (A(2) cytoplasm), and Cajanus cajanifolius (A(4) cytoplasm), were crossed to 7 pigeonpea (Cajanus cajan (L.) Millsp.) cultivars in a line x tester mating scheme to study the fertility restoration of the CMS lines. Twenty-one F(1) hybrid combinations were planted in ...

While many studies have evaluated the effect of medications on semen quality, there is little guidance as to what is the true impact of many medications on male fertility. Further well designed studies are required to elucidate the precise associations between certain therapeutic medications and their effect on male fertility. *Corresponding author: Yulian Zhao, PhD, MD, MBA, Johns Hopkins Univ...

In higher plants, the developmental programs of the male and female organs are substantially independent of each other and of the vegetative plant. This developmental independence permits the genetic dissection of fertility processes without impairing vegetative growth. Male fertility requires a number of coordinated developmental events. These include the formation, as part of the flower, of s...

BACKGROUND Cytogenetic abnormalities have been known to be important causes of male infertility for decades. METHODS Research publications from 1978 to 2008, from PubMed, have been reviewed. RESULTS These studies have greatly improved our information on somatic chromosomal abnormalities such as translocations, inversions and sex chromosomal anomalies, and their consequences to the cytogenet...

Spermatogenesis is a complex process that involves stem-cell renewal, genome reorganization and genome repackaging, and that culminates in the production of motile gametes. Problems at all stages of spermatogenesis contribute to human infertility. Male infertility, is characterized by hypogonadism, decreased semen quality or ejaculatory dysfunction, accounts for approximately 20% of infertility...

In the United States since 1980, the birth rate in women aged > 35 years has increased by nearly 60%, whereas the birth rate for women aged 20 to 34 years has increased by only 10%. The trend in parenthood at an older age has also been seen in men. Since 1980, the fertility rate for men in their 30s has increased by 21% and for men aged 40 years and older, the rate has increased nearly 30%. In ...

We are in the age of genetic discovery. Now the human genome has been completely sequenced1, there will be increasing understanding and ability to manipulate biochemical pathways downstream of genes. At the same time, further development of in vitro fertilization (IVF) and intracytoplasmic sperm injection(ICSI) will enable procreation in situations that were formerly impossible and when there m...