Mendel's First Law: also called Mendel's Law of Segregation. It states that during gameteplugin-autotooltip__default plugin-autotooltip_bigGamete: a specialized (usually haploid) cell used for sexual reproduction. Eggs (oocytes) and sperm are gametes. formation, the two allelesplugin-autotooltip__default plugin-autotooltip_bigAllele: a version of a gene. Alleles of a gene are different if they have differences in their DNA sequence. at a geneplugin-autotooltip__default plugin-autotooltip_bigGene: read Chapters 02, 03, 04, 05, and 06 for a definition of gene :-) locusplugin-autotooltip__default plugin-autotooltip_bigLocus (plural form: loci): a physical location of a gene; often used as a synonym for a gene. segregate from each toher; each gameteplugin-autotooltip__default plugin-autotooltip_bigGamete: a specialized (usually haploid) cell used for sexual reproduction. Eggs (oocytes) and sperm are gametes. has an equal opportunity of containing either alleleplugin-autotooltip__default plugin-autotooltip_bigAllele: a version of a gene. Alleles of a gene are different if they have differences in their DNA sequence..