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.
Tetrads only appear in meiosis. The tetrad is the joining of four chromosomes in prophase I of meiosis. Two male duplicated chromosomes and two female chromosomes. The most im â¦ portant role of tetrad formation is ' crossing over. ' This is the exchange of genetic information between the male and female chromosomes.