| 释义 |
independent assortment
independent assortment[‚in·də′pen·dənt ə′sȯrt·mənt] (genetics) In meiosis, the random assortment of the alleles at two or more loci because they are on different chromosome pairs or far apart on the same chromosome pair. independent assortment
in·de·pen·dent as·sort·mentthe pattern of transmission of unlinked loci. Fig. 196 Independent assortment . Separation of chromosomes. independent assortment the random arrangement and separation of chromosomes during MEIOSIS, giving all possible combinations in equal frequency, unlike the situation with GENETIC LINKAGE. The process is important in understanding MENDELIAN GENETICS and explains the random distribution in the gametes of genes or nonhomologous chromosomes. For example, take two pairs of HOMOLOGOUS CHROMOSOMES in a DIPLOID (1) cell. During anaphase 1 there are two ways in which the chromosomes can become separated (see Fig. 196 ). Independent assortment of the chromosomes in the Fig. gives four types of possible gamete (1 + 3), (2 + 4), (1 + 4) and (2 + 3). In fact, the number of combinations is 2 to the power of the number of pairs of chromosome, 22 = 4 in the above example. A human with 23 pairs of chromosomes would produce 223 = 8 388 608 combinations by independent assortment alone. |