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.
A tetrad is formed when two homologous chromosomes line up side by side (synapse). Each homologous chromosome has two sister chromatids held together at the centromere. So the tetrad has four chromatids all together. One homologous chromosome is singular-it is one chromosome.