Tandem fusion, a rare evolutionary chromosome rearrangement, has occurred extensively in muntjac karyotypic evolution, leading to an extreme fusion karyotype of 6/7 (female/male) chromosomes in the Indian muntjac. These fusion chromosomes contain numerous ancestral chromosomal break and fusion points. Here, we designed a composite polymerase chain reaction (PCR) strategy which recovered DNA fragments that contained telomere and muntjac satellite DNA sequence repeats. Nested PCR confirmed the specificity of the products. Two-color fluorescence in situ hybridization (FISH) with the repetitive sequences obtained and T2AG3 telomere probes showed co-localization of satellite and telomere sequences in Indian muntjac chromosomes. Adjacent telomere and muntjac satellite sequences were also seen by fiber FISH. These data lend support to the involvement of telomere and GC-rich satellite DNA sequences during muntjac chromosome fusions.

Twelve methods for analysing FCM-histograms were compared using the same set of data. Some of the histograms that were analysed were simulated by computer and some were taken from experiments. Simulated data were generated assuming asynchronously growing cell populations and (i) measurement coefficients of variation (CV) from 2 to 16%; (ii) constant measurement CV or CV's increasing from G, to G , phase, and (ii) varying fractions of cells in each phase. Simulated data were also generated assuming synchronous cell populations i n which a block in early S phase was applied and released. DNA histograms were measured for L-929 cells at various times after mitotic selection. Labelling indices were also measured for these cells at the same time.The fractions of cells in the G,, S, and (G2 + M) phases were calculated by each analytical method and compared with the actual fractions used for simulation, or in case of exp&rimental data., with autoradiographic results. Generally, all methods yielded reasonably accurate fractions of cells in each phase with relative errors in the range of 1&20%. However, most methods tended to overestimate G, fractions and underestimate S fractions. In addition, variations in the shape of the S phase distribution often caused considerable errors. Phase fractions were also calculated for histograms of kinetically perturbed populations, simulated as well as experimental The errors were only slightly larger than for histograms from asynchronously growing cell populations.Several methods for estimating cell-cycle-traverse parameters of DNA histograms generated from flow cytometry (FCM) have been published in the last few years (Dean

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Femtochemistry / Wavepacket Dynamics / Proton TransferUltrafast pump-probe experiments with a time-resolution of 30 fs have been carried out to explore the non-radiative relaxation dynamics of electronically excited 1,8-dihydroxyanthraquinone (DHAQ) in polar liquid solution. The results are discussed in terms of a Lippincott-Schroeder double-minimum potential along the proton-transfer reaction coordinate for the ground (S0) and first excited singlet states (S1) of DHAQ. The 400-nm pump-visible probe data reveal a strongly Stokes-shifted stimulated emission due to the proton-transferred 1,10-quinone configuration in the S1-state. A dominant fraction of this stimulated emission appears instantaneously implying that cross-well excitation directly from the ground-state 9,10-quinone form into the excited-state 1,10-quinone configuration takes place. A smaller fraction of the stimulated emission appears delayed with a time constant of approximately 300 fs. This component may be due to proton-transfer in the S 1 -state following optical excitation. Further, a transient absorption is observed on the red edge of the linear absorption spectrum of ground-state DHAQ due to higher-lying electronic states presumably from the 1,10-configuration. Periodic modulations of the transient absorption due to wavepacket motion in the 9,10-quinone form are partially consistent with previous fluorescence excitation spectra of the molecule taken under jetcooled conditions.