For those wanting to know what the new Snapchat emoji symbols mean, there is several different things that they repersent and these emojis have replaced the âBest Friendsâ feature with Friend Emojis smilies.
(plural tetrads) 1  A group of four things. ( 2 chemistry) A tetravalent atom or radical. ( biology) Two pairs of sister chromatids (a dyad pair) aligned in a certain way and often on the equatorial plane during the meiosis process.
The term tetrad is referring to the 4 chromatids present in the two replicated chromosomes that associate during prophase I of meiosis. Once crossing over has happened, the 4 chromatids are all genetically distinct from each other. During anaphase I, remember that the homologous chromosomes separate from each other.