Gene conversions in the horse alpha-globin gene complex

The sequences of the linked alpha 2- and alpha 1-globin genes of the equine BI and BII haplotypes are greater than 99% identical within a 1.2-kb region extending from approximately 75 bp upstream of the putative cap site to a point approximately 150 bp 3' to the poly A addition signal. Differences between the alpha 2 and alpha 1 genes that are common to both haplotypes indicate that a major gene conversion occurred approximately 12 Myr ago and that this has been followed by shorter, more localized, conversions. Interhaplotype (allelic) comparisons at the alpha loci suggest that the BI and BII haplotypes have probably existed independently greater than or equal to 0.5 Myr and that the alpha 1 genes may have undergone a recent interchromosomal gene conversion.      

Some aspects of the system of Haversian canals in the diaphysary compact bone in man

The general aspect of the network of Haversian canals was studied on tangential and radial sections from the diaphysary compact bone of the human long bones. The network-like aspect was much varied even in the same bone and at the same level from which the samples were obtained. No obvious differences were found between the studied bones or between the two limbs. Certain peculiarities of the canal system were noticed as regards the trajectory of canals, disposition and number of anastomoses, and the network aspect, depending on the region of the diaphysis, but especially on the depth.     

Isolation and Preliminary Characterization of the RNA-Containing R-Type, Virus-Like Particle of BHK-21 Cells

An R-type virus-like particle (VLP) has been isolated from the medium of BHK-21-F cells by ultracentrifugation and polyethylene glycol precipitation. The R-type VLP contains RNA which sediments at 60 to 70S in sucrose density gradients and has a molecular weight of approximately 10(7), as estimated by gel electrophoresis. The R-type VLP can be labeled with (3)H-uridine in the presence of actinomycin D. On the basis of morphology, site of maturation, and preliminary biochemical characterization, the R-type VLP does not appear to fit into any of the major groups of animal viruses.