نتایج جستجو برای: gametes
تعداد نتایج: 3227 فیلتر نتایج به سال:
OBJECTIVE To evaluate the use of fresh or frozen bovine oocytes as an animal model for reconstructing artificial gametes by germinal vesicle transplantation (GVT), to study nucleocytoplasmic interaction and define clinical procedures for ooplasm donation in humans. DESIGN Prospective experimental study. SETTING University-based experimental laboratory. ANIMAL(S) Bovine oocytes from slaugh...
Evolutionary theory predicts that the sex ratio of Plasmodium gametocytes will be determined by the number of gametes produced per male gametocyte (male fecundity), parasite clonal diversity and any factor that reduces male gametes' ability to find and combine with female gametes. Despite the importance of male gametocyte fecundity for sex ratio theory as applied to malaria parasites, few data ...
dear editor, today some infertile couples who want to have children have request for getting gametes which is a confidential process. according to law, no person must know the identity of the gamete providers (1). confidentiality of information relating to gamete and embryo donation can cause serious ethical problems. in some countries, forming the bank of gametes and embryos is intended as a w...
A class II transposable element, mPing exists in the rice genome ubiquitously and can transpose even in ordinary cultivation conditions. A copy of mPing was identified at the long arm of chromosome 12. In reciprocal backcrossed F1s between a heterozygote and a homozygote without mPing, the male gametes with this mPing from heterozygotes were transmitted to the next generation at a lower frequen...
The evolution of anisogamy (the production of gametes of different size) is the first step in the establishment of sexual dimorphism, and it is a fundamental phenomenon underlying sexual selection. It is believed that anisogamy originated from isogamy (production of gametes of equal size), which is considered by most theorists to be the ancestral condition. Although nearly all plant and animal ...
Previous studies on flagellar adhesion in chlamydomonas (Snell, W. and S. Roseman. 1979. J. Biol. Chem. 254:10820-10829.) have shown that as gametes adhere to flagella isolated from gametes of the opposite mating type, the adhsiveness of the added flagella but not of the gametes is lost. The studies reported here show that the addition of protein synthesis inhibitors (cycloheximide [CH] or anis...
Consider the genome structure of gametes in an advanced F t population descended from two inbred lines. these eight gametes can produce 36 diierent zygotes (27 discernible genotypes in practice). Assume that r, r 1 , and r 2 denote the recombination rates between A and C, betwe e n A a n d B a n d b e t ween B and C, respectively. Let 1 and 0 represent the capital and small-letter alleles, resp...
The practice of gamete donation has, until recently, been shrouded in secrecy. The stigma associated with infertility and, in particular, donor insemination has been the main factor contributing to this secrecy. Over the last 20 years, this secrecy and the anonymity of the gamete donors has been challenged. In the first instance, the challenge came from governments in some countries legislating...
This essay develops a framework for thinking about the moral basis for the commodification of human reproductive materials. It argues that selling and buying gametes and genes is morally acceptable although there should not be a market for zygotes, embryos, or genomes. Also a market in gametes and genes should be regulated in order to address concerns about the adverse social consequences of co...
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