Abstract The genetic selection is a form of optimization. Traits in explicit or implicit index are improved, while other traits change according to correlations among the traits. After long selection, usually production improve fitness deteriorate. At gene level, it seems that genes associated with positive effects on major tend fixation, and remaining large effect exhibit pleiotropy. While for...

Civilizations throughout the world continue to depend on pig meat as an important food source. Approximately 40% of the red meat consumed annually worldwide (94 million metric tons) is pig meat. Pig numbers (940 million) and consumption have increased consistent with the increasing world population (FAO 2002). In the past 50 years, research guided genetic selection and nutrition programs have h...

Most, but not all, studies report a positive association between birth weight, as an indirect marker of prenatal hormone exposure, and offspring breast cancer risk, particularly premenopausal breast cancer. Females from opposite-sexed twin pairs may also be prenatally exposed to androgens from their twin brothers. A Swedish study of opposite-sexed twins with a small sample size found a very str...

This paper reviews and examines emerging academic approaches to the study of ‘sexualized culture’; an examination made necessary by contemporary preoccupations with sexual values, practices and identities, the emergence of new forms of sexual experience and the apparent breakdown of rules, categories and regulations designed to keep the obscene at bay. The paper maps out some key themes and pre...

the aim of this study was to evaluate the effects of the addition of antioxidants (vitamin e, β- mercaptoethanol and their combination) to semen extender.  progressive motility, viability and ph of fresh ram semen were examined. ejaculate samples were collected with artificial vagina from three ghezel-merinose rams (3 years old) during non- breeding reproduction season. semen was diluted with a...

BACKGROUND There is evidence to suggest a masculinizing effect on female intrauterine development in unlike-sexed twins. The purpose of the present report was to examine the possible effects of male presence on fetal growth in females by comparing mean birthweights in members from dizygotic unlike-sexed (DZU) pairs with those from dizygotic like-sexed (DZL) pairs. METHODS The sample consisted...

Sperm dimensions and the question of whether X and Y chromosome-bearing sperm differ in size or shape has been of great interest, especially for the development of alternative methods to sort or classify sperm cells. The aim of the present study was to evaluate possible differences in the shape and size of the sperm head between X and Y chromosome-bearing sperm by atomic force microscopy (AFM)....