pronucleusn.
/(ˌ)prəʊˈnjuːklɪəs/, U.S. /ˌproʊˈn(j)ukliəs/ Cell Biology.
Either of a pair of haploid gametic nuclei at a stage before their fusion leads to the formation of the diploid nucleus of the zygote.
ΘΚΠ
the world > life > biology > biological processes > procreation or reproduction > reproductive substances or cells > [noun] > reproductive cell > nucleus of
pronucleus1876
the world > life > biology > biological processes > procreation or reproduction > reproductive substances or cells > [noun] > gametes > nucleus of
pronucleus1876
1876 E. Van Beneden in Q. Jrnl. Microsc. Sci. 16 154 The first nucleus is developed at the expense of a body formed in the cortical layer of the ovum, which I have called the peripheral pronucleus.
1918 B. F. Kaupp Anat. Domest. Fowl 320 After the pronucleus has united with the female pronucleus in the single-celled ovum, there is a cleavage of the cell in the long axis of the egg.
1940 G. S. Carter Gen. Zool. Invertebr. xx. 396 The pronucleus of the sperm enters the egg and fuses with the egg pronucleus to form the zygote.
1969 Observer 16 Feb. 1/6 Instead of containing two ‘pronuclei’—one formed from the nucleus of the sperm cell, the other from the egg's nucleus—they [sc. the fertilised eggs] had several.
2005 Lab Business Week (Nexis) 3 Apr. 296 The lack of cyclin B1 in the oocyte led to activation in 10% of the oocytes as evidenced by the presence of a pronucleus.
Derivatives
proˈnucleate adj. of or relating to a pronucleus; esp. (of a zygote) at the stage of having two distinct pronuclei.
ΚΠ
1890 Cent. Dict. Pronucleate, having a pronucleus or pronuclei.
1957 Proc. Royal Soc. B. 146 497 Most of the pronucleate eggs..had two normal pronuclei.
2001 Jrnl. Assisted Reprod. & Genetics 18 235/1 Postthaw survival rates and blastocyst formation rates were compared between the three substages and the pronucleate and the 2-cell stage embryos.
This entry has been updated (OED Third Edition, June 2007; most recently modified version published online March 2022).
<
n.1876