The Genetics of the Frankia-Actinorhizal Symbiosis
Peter M. Gresshoff in Molecular Biology of Symbiotic Nitrogen Fixation, 2018
So far, DNA-DNA hybridization techniques have demonstrated the following: Among Frankia strains, the nifH gene appears to be more conserved than is the nifD gene, and the nifD gene is more conserved than the nifK gene. The observations agrees with what has been described by Hennecke et al.58 for other nitrogen-fixing bacteria.The nifK gene exhibits some sequence similarity to the nifD gene.58a Similarity between the two MoFe protein genes has been described previously for Bradyrhizobium japonicum by Thony et al.59 who postulated a common ancestry.Frankia strain ARgP5Ag (ULQ0132105009) has a different organization of nif genes compared to the "typical" Frankia strains.60Nif DNA probes were found to hybridize to a 10-kb EcoRI fragment on total DNA blots and also to a 5.6-kb EcoRI fragment from a large (190 kb) indigenous plasmid.
Which ethics for the fetus as patient?
Dagmar Schmitz, Angus Clarke, Wybo Dondorp in The Fetus as a Patient, 2018
‘Individuality’ can have several meanings. It can be understood as genetic, biological, psychological, numerical, and physical individuality (Hucklenbroich, 2003). A human being can, for example, be considered an individual because he or she has a unique genetic make-up unlike those of other human individuals. The genes that code for our individual phenotypes render us distinct from each other. With its individual genome and resulting individual phenotype, the fetus is a genetic individual. Even when there is a genetic twin, epigenetic effects and new (post-conception) mutations make him or her a unique individual in comparison to all other genetic subjects. In a biological sense, ‘individuality’ can be understood as being a member of a kind, e.g., one example of the species Homosapiens. Species are groups of organisms that share certain traits, such as a common ancestry. Since the fetus shares the traits that are typical for the group of organisms we call ‘humans’, it is a true member of that group. Understood in a psychological sense, ‘individuality’ refers to the psychological events – perceptions, thoughts and memories – human beings experience through the course of their lifetimes. By the time the nervous system begins to develop, it can be assumed that fetuses have mental experiences and start developing individual personalities, which makes them to individuals in the psychological sense, too.
Genetics
Stephan Strobel, Lewis Spitz, Stephen D. Marks in Great Ormond Street Handbook of Paediatrics, 2019
Autosomal recessive inheritance is depicted inFig. 15.16. There is a 25% risk of an affected child in any pregnancy, independent of gender. The diagram in (B) illustrates a consanguineous relationship between first cousins. A common ancestor is a carrier for a recessive mutation that may occur in homozygous form in a descendent as a consequence of consanguinity. Natural history: dependent on the specific condition.Differential diagnosis: dependent on the specific condition.Treatment/Management/Surveillance: carrier testing for the wider family.prenatal diagnosis is often possible in future pregnancies.
Longitudinal phenotypic study of late-onset retinal degeneration due to a founder variant c.562C>A p.(Pro188Thr) in the C1QTNF5 gene
Published in Ophthalmic Genetics, 2021
Julie De Zaeytijd, Frauke Coppieters, Marieke De Bruyne, Jasper Van Royen, Dimitri Roels, Rani Six, Caroline Van Cauwenbergh, Elfride De Baere, Bart P. Leroy
Twenty-six family members were included in the study, initially presenting as part of three seemingly unrelated families. In 25 family members, a diagnosis of L-ORD was molecularly confirmed. Patient V5 with an L-ORD phenotype was deceased prior to DNA-analysis. In each family, sequencing of the coding region of the C1QTNF5 gene identified the c.562C>A p.(Pro188Thr) variant in a clinically affected individual. Thereafter, molecular analysis of the variant proved segregation with disease in others. To establish an unequivocal relationship between the presence of the mutation and a clinical phenotype of L-ORD and to exclude the possibility of non-penetrance of the variant, a sub-analysis of all family members above the age of 40 revealed the presence of the variant in 20 clinically affected individuals and the absence of the variant in 10 clinically unaffected family members. This proved that the variant c.562C>A p.(Pro188Thr) in C1QTNF5 was the causal mutation and confirmed L-ORD to be a 100% penetrant disease. Additional testing revealed the presence of this variant in six asymptomatic and clinically unaffected individuals. All family members were descended from ancestors from a formerly geographically and thus genetically isolated area in Belgium. Therefore, a common ancestry was suspected. SNP-based haplotyping in four heterozygous individuals, distantly related, revealed a common haplotype with a size of 9.7–11.4 Mb (Figure S1), and a genealogical investigation identified a common ancestor, rendering c.562C>A p.(Pro188Thr) a Belgian founder variant.
Genetic diversity of 15 autosomal STRs in a sample of Berbers from Aurès region in the Northeast of Algeria and genetic relationships with other neighbouring samples
Published in Annals of Human Biology, 2020
Amine Abdeli, Traki Benhassine
Moreover, a genetic similarity was found among three Algerian Berber groups (Chaouis, Kabyles, and Mozabites). Although these groups represent different cultural and spoken dialects, there is no clear pattern of genetic differentiation between them. The absence of differentiation among these Berber groups was also noted using Alu insertion markers (Badache et al. 2019), and our data also failed to show any significant differentiation between groups according to their geographic regions (Northeast vs. South). These similarities indicate that our samples could share a common ancestor who was either autochthonous North African with gene flow from populations who have conquered or migrated in North Africa during prehistory and history, or who arrived in North Africa and then experienced gene flows from the surrounding regions.
Analysis of uniparental markers reveals a complex pattern of migration within Sardinia
Published in Annals of Human Biology, 2018
Renato Robledo, Giuseppe Vona, Emanuele Sanna, Valeria Bachis, Carla Maria Calò
The Island of Sardinia, in the Mediterranean Sea, has been subject to intensive research in the fields of genetics and anthropology (see www.sardoa.eu). From the genetic viewpoint, the Sardinian population has always been described as a major outlier. Indeed, its genetic structure is very different from any other European population (Anagnostou et al. 2017; Lacerenza et al. 2017). This is mainly due to genetic drift, since, throughout history, Sardinians had negligible contact with the surrounding populations (Vona 1997; Vona and Calò 2006). The present population of Sardinia, amounting to 1 639 362 individuals (I.S.T.A.T. 2011), is distributed in a few large urban aggregates of recent formation and in a much larger number of small villages (Siniscalco et al. 1999). These isolated communities, in spite of their common ancestry, have been diversified by centuries of isolation, often in quite different ecological environments. The long-term isolation, due to both geographical barriers and cultural factors, accounts for a high rate of endogamy that enhanced the effect of drift, thus contributing to the genetic heterogeneity observed within the island (Cappello et al. 1996; Capocasa et al. 2014; Robledo et al. 2015).
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