EGL USA is one of the largest and oldest independent gemological institutions focusing on gemstone certification and research. Originally part of an international network founded in Europe in 1974, EGL USA opened its first U.S. lab in the heart of New York's international diamond and jewelry district in 1977.
the fusion of the nucleus of a haploid sperm cell and the nucleus of a haploid egg cell, forming a diploid zygote zygote diploid cell formed when the nucleus of a haploid sperm cell fuses with the nucleus of a haploid egg cell tetrad group of four chromatids formed during prophase I of meiosis by the two sister chromatids in each of the two homologous chromosomes
Several points of fusion occur between the plasma membranes of the two gametes (i.e., the breakdown of membranes occurs by formation of numerous small vesicles). Specificity of sperm-egg interaction Fertilization is strictly species-specific, and the eggâs coating, the zona pellucida, plays an important role in the binding process between sperm and egg.