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Joined 2026-09-21 Message
Incoming links: Gametogenesis
Gametogenesis 2026-11-05
Gametogenesis is the development and differentiation of gametes, the biological cells that fuse during fertilization. It includes preparation of specialized cellular structures as well as changes in chromosome number where these occur. Gametogenesis and meiosis are therefore related processes, not interchangeable names.
In the usual animal life cycle, a diploid germ line undergoes meiosis in producing haploid gametes. In plants with alternation of generations, meiosis instead produces spores; the haploid gametophyte then produces gametes through development involving mitosis. Research on MOS7 in Arabidopsis thaliana showed that disrupted microtubule organization during these postmeiotic divisions can impair both male and female gametophyte development.[ref]
Nucleoporin MOS7/Nup88 is required for mitosis in gametogenesis and seed development in Arabidopsis by Guen Tae Park and others. PNAS 111, pp. 18393–18398; mitotic defects during male and female gametogenesis
Ndt80 2026-11-05
Ndt80 is a transcription factor in Saccharomyces cerevisiae that activates a set of genes needed for progression through meiosis and gametogenesis. It is encoded by the NDT80 gene. Its role links a developmental transition to coordinated gene expression, rather than to completion of a single structural event.
The initial 1995 study found that NDT80 gene mutants arrested at pachytene, a stage of meiotic prophase. Their homologous chromosomes remained joined by full-length synaptonemal complexes. Much of meiotic recombination still occurred, showing that chromosome exchange and progression out of this stage could be experimentally separated.[ref]
NDT80, a meiosis-specific gene required for exit from pachytene in Saccharomyces cerevisiae by L. Xu and others. Molecular and Cellular Biology 15, pp. 6572–6581; mutant phenotype and recombination analysis
A 1998 study then connected the phenotype to transcriptional control. Producing Ndt80 outside its normal developmental setting induced target genes, while the isolated protein bound a conserved upstream DNA sequence. The combination of altered gene expression and sequence binding supported a direct regulatory role.[ref]
Gametogenesis in yeast is regulated by a transcriptional cascade dependent on Ndt80 by S. Chu and others. Molecular Cell 1, pp. 685–696; ectopic expression and binding by recombinant Ndt80
Semen Created 2026-10-31 Updated 2026-11-05
Semen is the fluid discharged by the male reproductive tract during ejaculation. In humans it normally contains sperm suspended in secretions from reproductive glands, including the prostate and seminal vesicles. Semen is therefore a mixture, whereas a sperm is an individual gamete.[ref]
Semen in the Medical Subject Headings. Scope note, D012661
Fluid volume and the number or movement of sperm describe different properties. A sample can contain fluid but few or no sperm, so visible semen alone does not establish successful gametogenesis or fertilization.