RESUMO
The separation of germ cell populations from the soma is part of the evolutionary transition to multicellularity. Only genetic information present in the germ cells will be inherited by future generations, and any molecular processes affecting the germline genome are therefore likely to be passed on. Despite its prevalence across taxonomic kingdoms, we are only starting to understand details of the underlying micro-evolutionary processes occurring at the germline genome level. These include segregation, recombination, mutation and selection and can occur at any stage during germline differentiation and mitotic germline proliferation to meiosis and post-meiotic gamete maturation. Selection acting on germ cells at any stage from the diploid germ cell to the haploid gametes may cause significant deviations from Mendelian inheritance and may be more widespread than previously assumed. The mechanisms that affect and potentially alter the genomic sequence and allele frequencies in the germline are pivotal to our understanding of heritability. With the rise of new sequencing technologies, we are now able to address some of these unanswered questions. In this review, we comment on the most recent developments in this field and identify current gaps in our knowledge.
Assuntos
Células Germinativas , Meiose , Evolução Biológica , Genoma , Meiose/genética , MutaçãoRESUMO
BACKGROUND: The domestic pig (Sus scrofa) is important both as a food source and as a biomedical model given its similarity in size, anatomy, physiology, metabolism, pathology, and pharmacology to humans. The draft reference genome (Sscrofa10.2) of a purebred Duroc female pig established using older clone-based sequencing methods was incomplete, and unresolved redundancies, short-range order and orientation errors, and associated misassembled genes limited its utility. RESULTS: We present 2 annotated highly contiguous chromosome-level genome assemblies created with more recent long-read technologies and a whole-genome shotgun strategy, 1 for the same Duroc female (Sscrofa11.1) and 1 for an outbred, composite-breed male (USMARCv1.0). Both assemblies are of substantially higher (>90-fold) continuity and accuracy than Sscrofa10.2. CONCLUSIONS: These highly contiguous assemblies plus annotation of a further 11 short-read assemblies provide an unprecedented view of the genetic make-up of this important agricultural and biomedical model species. We propose that the improved Duroc assembly (Sscrofa11.1) become the reference genome for genomic research in pigs.
Assuntos
Biologia Computacional/métodos , Genoma , Genômica/métodos , Análise de Sequência de DNA/métodos , Sus scrofa/imunologia , Animais , Anotação de Sequência Molecular , Reprodutibilidade dos Testes , Pesquisa , SuínosRESUMO
The structure and organization of a species genome at a karyotypic level, and in interphase nuclei, have broad functional significance. Although regular sized chromosomes are studied extensively in this regard, microchromosomes, which are present in many terrestrial vertebrates, remain poorly explored. Birds have more cytologically indistinguishable microchromosomes (~ 30 pairs) than other vertebrates; however, the degree to which genome organization patterns at a karyotypic and interphase level differ between species is unknown. In species where microchromosomes have fused to other chromosomes, they retain genomic features such as gene density and GC content; however, the extent to which they retain a central nuclear position has not been investigated. In studying 22 avian species from 10 orders, we established that, other than in species where microchromosomal fusion is obvious (Falconiformes and Psittaciformes), there was no evidence of microchromosomal rearrangement, suggesting an evolutionarily stable avian genome (karyotypic) organization. Moreover, in species where microchromosomal fusion has occurred, they retain a central nuclear location, suggesting that the nuclear position of microchromosomes is a function of their genomic features rather than their physical size.
Assuntos
Aves/genética , Cromossomos/ultraestrutura , Genoma , Filogenia , Sintenia , Animais , Evolução Biológica , Aves/classificação , Coloração Cromossômica/métodos , Cariotipagem , Recombinação Genética , Especificidade da EspécieRESUMO
This article discusses a scoping study on implementing radio frequency identification device (RFID) in a hospital library context, conducted by Joseph Norwood for his MA dissertation at the University of Brighton. The study was carried out during the summer of 2011 to support possible RFID implementation at the Brighton and Sussex University Hospitals (BSUH) Trust, and the library staff were able to use the findings to good effect to create a business plan. This article also acts as the template for the new Dissertations into Practice feature, which was introduced in the March issue (Marshall, A. Health Information and Libraries Journal 2012, 29, 72). The dissertation highlighted here is very practical in nature and had immediate and quantifiable benefits for the Trust library. Future feature articles are likely to reflect the range of health-related dissertation topics which students choose and will include studies on user information behaviour, information services related to mental health and well-being, as well as the impact of technology on health-related library or information services.AM.