Five Generations of congenital Stationary Night-blindness in an American family

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Pi Zpratt : A new alpha1-antitrypsin allele in an American negro family

Summary A low-power laser-UV microbeam of wave-length 257 nm was used for microirradiation of a small part of the nucleus of Chinese hamster cells. Following fixation in interphase or in the subsequent metaphase indirect immunofluorescent staining was performed with antiserum to photoproducts of DNA treated with far UV light.The results show that antibodies specific for UV-irradiated DNA can be used for a direct detection of laser-UV microirradiation-induced DNA photolesions. The potential usefulness of this method for investigation of the spatial arrangement of chromosomes in the interphase nucleus is discussed.     

The Descent of Rights and the Descent of Persons

Explication and evaluation of the relative ethnographic and theoretical merits of several constructions of "descent" and "descent groups" (by W. H. R. Rivers, M. Fortes, and W. Goodenough, among others) reveals that relations of descent can have right and duty values only where patri- or matrifiliation is the necessary and sufficient condition for inclusion in a social group. Therefore, only unilineally constituted groups should be described as descent groups.     

An Assessment of the Effectiveness of Straw as an Algal Inhibitor in an Upland Scottish Loch

The control of algal blooms caused by a colony of black-headed gulls in an upland loch in central Scotland was attempted using bales of barley straw. The initial evidence suggests that the release of the inhibitory substance commenced 6-10 months after placement of the bales and was sustained for at least 18 months. The moored bales provided a useful substrate for benthic invertebrates, acting as a shelter and detritus trap. Algal diversity appeared not to be affected by the bales, but the cell numbers of the main species were affected.     

Identity by Descent in Island-Mainland Populations

A new model is presented for the genetic structure among a collection of island populations, with fluctuating population sizes and continuous overlapping generations, using a stochastic birth, death and immigration (BDI) process. Immigrants enter each island from a large mainland population, with constant gene frequencies, according to a Poisson process. The average probability of identity by descent (IBD) for two haploid individuals randomly selected from an island population is f(0) = (f(1) + λ)/( + λ), where f(1) is the probability of IBD for two randomly selected immigrants, λ is the birth-rate for each individual, and is the arrival rate of immigrants into each island. The value of f(0) is independent of the death process, time and N. The expected level of genetic differentiation among island populations is F(ST) = (1 - 1/n)λ/( + λ), where n is the total number of islands receiving immigrants. Because f(0) and F(ST) are independent of the death process, for a BDI model, the population genetic structure for several general demographic situations may be examined using our equations. These include stochastic exponential, or logistic (regulated by death rate) growth within islands, or a ``source-sink' population structure. Because the expected values of both f(0) and F(ST) are independent of time, these are achieved immediately, for a BDI model, with no need to assume the island populations are at genetic equilibrium.     

Descent of a split RNA

tmRNA is found in the usual one-piece form in most cyanobacteria, but a small clade has an unusual two-piece form, resulting from processing of a circularly permuted precursor RNA. Here, the secondary structure of the cyanobacterial one-piece tmRNA is established by phylogenetic sequence comparison; it deviates from most tmRNAs in having an extra (fifth) pseudoknot and a branched structure at the end of the tag reading frame. Patterns of sequence conservation between the two cyanobacterial tmRNA types suggest particular events in the evolution of the two-piece form. A simple gene permutation model of tandem duplication followed by loss of the outermost segments appears inadequate. An additional rearrangement is proposed, in which a structure impaired by deletion was regenerated at the expense of a neighboring structure.