Isolation and characterization of microsatellites in Pacific white shrimp Penaeus (Litopenaeus) vannamei

Five polymorphic microsatellite loci were characterized for Penaeus (Litopenaeus) vannamei. Loci were isolated using a partial Sau3A1 genomic library by the sequencing of randomly selected clones and by a biotinylated (CT)₁₀ and (GT)₁₀ probes screening procedure. The last strategy resulted in the most useful data. About 40% of the clones showed a previously reported satellite/microsatellite (PVS1), reducing the chance of finding new microsatellite regions. Whereas two of the microsatellite loci with more than 10 alleles will be useful for mating analysis in a breeding program, the others might prove useful for population genetic studies.     

The NADP-dependent trifunctional methylenetetrahydrofolate dehydrogenase purified from mouse liver is immunologically distinct from the mouse NAD-dependent [corrected] bifunctional enzyme

Methylenetetrahydrofolate dehydrogenase - methenyltetrahydrofolate cyclohydrolase - formyltetrahydrofolate synthetase was purified to homogeneity from mouse liver, taking advantage of its very high affinity for 2',5'-ADP-Sepharose. Antibodies raised to this trifunctional enzyme and to the bifunctional NAD-dependent dehydrogenase-cyclohydrolase from mouse Ehrlich ascites tumour cells were found not to cross-react with the purified proteins on Western blots. Each of these polyclonal antibodies detects the appropriate protein in extracts of Ehrlich ascites tumour cells after sodium dodecyl sulfate - polyacrylamide gel electrophoresis and electrophoretic transfer of the proteins to nitrocellulose. The procedure has also been used to obtain a purified preparation of the trifunctional enzyme from human liver obtained at autopsy.     

Cell kinetics of a chondrosarcoma.

The cell kinetics of the transplantable DC-II mouse chondrosarcoma have been studied by the pulse labelled mitoses method. The analysis gave the following estimates for the phases of the cell cycle: G1, 10-5 hr; S, 9-5 hr; G2, 4 hr with an intermitotic time of 23-5 hr. Consideration of the overall growth of the tumour indicated that the growth fraction and cell loss factor both had values of about 0-5. The results are compared with cell kinetic data from sarcomas and other cartilage tissues.     

Cell Kinetics and the Control of Growth In Long Bones

The cell kinetics of the cartilage growth plate are outlined and discussed in terms of the probable levels of control on the system. Possible mechanisms of growth control at the cellular level are examined for (i) the rate of cell division in the proliferation zone, (ii) the command to differentiate that limits the size of the proliferation zone and (iii) the ageing process in the cartilage plate. the evidence of cell kinetics does not point unequivocally to any particular mechanism.     

Ancestral haplotype reconstruction in endogamous populations using identity-by-descent

In this work we develop a novel algorithm for reconstructing the genomes of ancestral individuals, given genotype or sequence data from contemporary individuals and an extended pedigree of family relationships. A pedigree with complete genomes for every individual enables the study of allele frequency dynamics and haplotype diversity across generations, including deviations from neutrality such as transmission distortion. When studying heritable diseases, ancestral haplotypes can be used to augment genome-wide association studies and track disease inheritance patterns. The building blocks of our reconstruction algorithm are segments of Identity-By-Descent (IBD) shared between two or more genotyped individuals. The method alternates between identifying a source for each IBD segment and assembling IBD segments placed within each ancestral individual. Unlike previous approaches, our method is able to accommodate complex pedigree structures with hundreds of individuals genotyped at millions of SNPs.We apply our method to an Old Order Amish pedigree from Lancaster, Pennsylvania, whose founders came to North America from Europe during the early 18th century. The pedigree includes 1338 individuals from the past 12 generations, 394 with genotype data. The motivation for reconstruction is to understand the genetic basis of diseases segregating in the family through tracking haplotype transmission over time. Using our algorithm thread, we are able to reconstruct an average of 224 ancestral individuals per chromosome. For these ancestral individuals, on average we reconstruct 79% of their haplotypes. We also identify a region on chromosome 16 that is difficult to reconstruct—we find that this region harbors a short Amish-specific copy number variation and the gene HYDIN. thread was developed for endogamous populations, but can be applied to any extensive pedigree with the recent generations genotyped. We anticipate that this type of practical ancestral reconstruction will become more common and necessary to understand rare and complex heritable diseases in extended families.