Preferential late replication of one of the two morphologically distinguishable X-chromosomes in a female muntjac

In a female barking deer, Muntiacus muntjak, whose 2 X-chromosomes are mutually distinguishable from each other, one X has been found to be late replicating in 57.8% cells compared to the other which is late replicating in 42.2% cells. These data are suggestive of preferential inactivation of one X-chromosome. These findings have been discussed in the light of Lyon's hypothesis of random X-inactivation in eutherian mammals.

Unique multiple sex chromosomes of the tree mouse Vandeleuria o. oleracea: identification of X1 and X2

The tree mouse Vandeleuria o. oleracea has an odd diploid chromosome complement (2n = 29 female/male) accompanied by a unique multiple sex-chromosome mechanism (X1X2Ymale/X1X1X2female). In the present paper the sex chromosomes have been identified unequivocally with the help of G-banding and DNA replication patterns which confirm our earlier suggestion that the X1 is smaller in size than the simple mammalian X, and also that the combined sizes of the X1 and X2 (3-8 and 1-7 per cent respectively) approximate to the size of the conservative mammalian X (5 per cent). It is proposed that the mammalian X has attained a minimum functional size so that further reduction is not tolerated.

DIPOLE MOMENTS AND STRUCTURE OF MOLECULAR COMPOUNDS: PART I. ALIPHATIC AND AROMATIC AMINE PICRATES

Dipole moment measurements have been made for some aliphatic and aromatic amine picrates in dioxane solution. The fractional ionic character of these complexes in the ground state has been calculated from μN, the observed value of dipole moment; μ0, the vector sum of the moments of the components of the complex; μ1, the moment resulting from complete one-electron transfer; and known values of S, using the charge-transfer theory of Mulliken. For these complexes of the n + hσd type, the charge-transfer process lies in the direction of the symmetry axis N+O−, the picture corresponding to an energy of interaction U, versus charge-transfer co-ordinate (C) curve with a shallow minimum showing an inner complex corresponding to (C = 1), b = a2 or b2 > a2, and an activated complex (roughly between C = 0.3 to 0.5) corresponding to an intermediate.