A new approach to quantitative analysis of somatic association

Abstract

A formula is proposed for estimating statistically the degree of somatic chromosome association during metaphase. Standard chi-square tests can then be used to determine the presence or absence of somatic association between homologous chromosomes in selected species. The method requires that the chromosomes be morphologically distinguishable and that their circular arrangement on the metaphase plate has not been distorted by the squash used during their preparation.

Studies on chromosome arrangement in some higher plants. III. Haplopappus gracilis (2n=4) and Crepis capillaris (2n=6).

“…If it is assumed that the chromosomes are arranged randomly, the occurrence of the pattern I may be twice as frequent as that of the pattern 2 (cf. Lacadena et al 1977), and thus 2/3 of the total examined cells would show the arrangement of pattern 1, and the rest 1/3 would show the pattern 2. However, Table 1.…”

Non-random segregation during anaphase II in an individual of Arcyptera tornosi (Bol.) (Orthoptera) heterozygous for three supernumerary heterochromatic segments

“…I n this individual we have not had the opportunity to establish a statistical correlation between the different types of anaphase II segregations, and the position of the half-bivalents in the metaphase II plates since the number of the latter was very small. Anyway, taking into account some studies about the chromosome distribution in radial metaphases II of grasshoppers (Nur, 1973;Lacadena et al, 1977) we now intend to analyze this particular aspect.…”

Random arrangement of mitotic chromosomes in radial metaphases of the Indian muntjac

“…two, and three pairs of homologs adjacent, respectively) are computed in a paper by Lacadena et al (1977). The expected frequencies for patterns within each class are equal to one another.…”