Purified chloroplast tRNAs were isolated fromPisum sativum leaves and radioactively labeled at their 3' end using tRNA nucleotidyl transferase and α(32)P-labeled CTP. Pea ctDNA was fragmented using a number of restriction endonucleases and hybridized with thein vitro labeled chloroplast tRNAs by DNA transfer method. Genes for tRNAs have been found to be dispersed throughout the chloroplast genome. A closer analysis of the several hybrid regions using recombinant DNA plasmids have shown that tRNA genes are localized in the chloroplast genome in both single and multiple arrangements. Two dimensional gel electrophoresis of total ct tRNA have identified 36 spots. All of them have been found to hybridize withPisum sativum ctDNA. Using recombinant clones, 30 of the tRNA spots have been mapped inPisum sativum ctDNA.

The genomic architecture underlying the origins and maintenance of biodiversity is an increasingly accessible feature of species, due in large part to third-generation sequencing and novel analytical toolsets. Woodrats of the genus Neotoma provide a unique opportunity to study how vertebrate herbivores respond to climate change, as two sister species (N. bryanti and N. lepida) independently achieved a major dietary feat — switching to the novel and toxic food source creosote bush (Larrea tridentata) — in the aftermath of a natural warming event. To better understand the genetic mechanisms underlying this ability, we employed a trio binning sequencing approach with a N. bryanti × N. lepida F1 hybrid, resulting in phased, chromosome-level, highly complete, haploid genome assemblies for each species from one individual. Using these new assemblies, we explored the genomic architecture of three cytochrome p450 subfamilies (2A, 2B, and 3A) that play key roles in the metabolism of naturally occurring toxic dietary compounds. We found that woodrats show expansions of all three p450 gene families, including the evolution of multiple novel gene islands within the 2B and 3A subfamilies. Our assemblies demonstrate that trio binning from an F1 hybrid rodent effectively recovers parental genomes from species that diverged more than a million years ago. Turnover and novelty in detoxification gene islands in herbivores is widespread within distinct p450 subfamilies, and may have provided the crucial substrate for dietary adaptation during environmental change.

15Birds and other vertebrates display stunning variation in pigmentation patterning, yet the 16 genes controlling this diversity remain largely unknown. Rock pigeons (Columba livia) 17 are fundamentally one of four color pattern phenotypes, in decreasing order of melanism: 18 T-check, checker, bar (ancestral), or barless. Using whole-genome scans, we identified 19 NDP as a candidate gene for this variation. Allele-specific expression differences in NDP 20indicate cis-regulatory differences between ancestral and melanistic alleles. Sequence 21 comparisons suggest that derived alleles originated in the speckled pigeon (Columba 22 guinea), providing a striking example of introgression of alleles that are favored by 23 breeders and are potentially advantageous in the wild. In contrast, barless rock pigeons 24have an increased incidence of vision defects and, like two human families with 25 hereditary blindness, carry start-codon mutations in NDP. In summary, we find 26 unexpected links between color pattern, introgression, and vision defects associated with 27 regulatory and coding variation at a single locus. 28