Search results for "Polymorphism"

In vitro rescue of zygotic embryos of sour orange, Citrus aurantium L., and their detection based on RFLP analysis

1998

Embryo development in vivo has been studied in four Citrus aurantium L. polyembryonic genotypes. Seeds were collected 65, 85, 105, 125 and 220 days after pollination (DAP). None of the immature seeds harvested 65 and 85 DAP contained visible embryos. A single embryo at a more advanced developmental stage was observed in the central position at the micropylar apex of the embryo sac in about 74% of seeds harvested at 105 DAP, while at 125 and 220 DAP the majority of seeds had two or more embryos at the same developmental stage crowded together. Restriction fragment length polymorphism (RFLP) analysis of low- and high-copy-number nuclear DNA was used to distinguish zygotic from nucellar seedli…

Patterns of Puffing Activity in the Polytene Chromosomes of Drosophila Subobscura

1982

The puffs and Balbiani rings are the visible expression of sites of genetic activity (Beerman, 1952). Since Beermann’s original hypothesis, puffing patterns for several species of Diptera have been described. Thus for the genus Drosophila, Ashburner (1967, 1969a and 1969b) has reported the puffing pattern of Drosophila melanogaster and Drosophila simulans, Beredens (1965) of Drosophila hydei, and Moriwaki and Ito (1969) of Drosophila ananassae. In a previous paper Frutos and Latorre (1981) have determined puffing patterns of the J and U chromosomes of Drosophila subobscura. This species shows a rich chromosomal polymorphism and the puffing pattern of several chromosomal rearrangements of th…

Epistatic interactions between pterin and carotenoid genes modulate intra-morph color variation in a lizard.

2021

Color polymorphisms have become a major topic in evolutionary biology and substantial efforts have been devoted to the understanding of the mechanisms responsible for originating such colorful systems. Within-morph continuous variation, on the other hand, has been neglected in most of the studies. Here, we combine spectrophotometric/visual modeling and genetic data to study the mechanisms promoting continuous variation within categorical color morphs of Podarcis muralis. Our results suggest that intra-morph variability in the pterin-based orange morph is greater compared to white and yellow morphs. We also show that continuous variation within the orange morph is partially discriminable by …

Geographic variation in the warning signals of the wood tiger moth (Parasemia plantaginis; Arctiidae)

2013

Many forms of the wood tiger moth (Parasemia plantaginis) : selective heterogeneity favours polymorphic warning signals

2013

Nonlinear optical properties of diaromatic stilbene, butadiene and thiophene derivatives

2021

Series of highly polar stilbene (1a–e), diphenylbutadiene (2a–c) and phenylethenylthiophene (3a–c) derivatives were prepared via Horner–Wadsworth–Emmons method with a view to produce new and efficient materials for second harmonic generation (SHG) in the solid-state. The single-crystal X-ray structures of compounds 1–3 reveal extensive polymorphism and a peculiar photodimerization of the 2-chloro-3,4-dimethoxy-4′-nitrostilbene derivative 1a to afford two polymorphs of tetra-aryl cyclobutane 4. The stilbene congeners 2-chloro-3,4-dimethoxy-4′-nitrostilbene (1a·non-centro), 5-bromo-2-hydroxy-3-nitro-4′-nitrostilbene (1b) and 4-dimethylamino-4′-nitrostilbene (1e), as well as 4′-fluoro-4′′-nitr…

Role of Cytokine Polymorphisms in the Rhinitis-Asthma Evolution

2014

AAD1. Role of Cytokine Polymorphisms in the Rhinitis-Asthma Evolution G. Santini1, L. Scola1, S. La Piana1, P. Di Gangi1, L. Vaccarino1, M. Bova1, C. R. Balistreri1, D. Lio1, G. Di Lorenzo1 1University of Palermo, Palermo, Italy Background: Several epidemiological studies demonstrate that a timeline from rhinitis to asthma exists, and that rhinitis is a risk factor for asthma. In particular, rhinitis increases the chance of development of asthma by about three times. In addition to environmental factors, genetic factors play an important role in the development of atopic airway diseases. The aim of this study is to analyse the role of cytokine polymorphism in the evolution of rhinitis-asthm…

Type 1 Diabetes and Autoimmune Thyroid Disease—The Genetic Link

2021

Type 1 diabetes (T1D) and autoimmune thyroid disease (AITD) are the most frequent chronic autoimmune diseases worldwide. Several autoimmune endocrine and non-endocrine disorders tend to occur together. T1D and AITD often cluster in individuals and families, seen in the formation of autoimmune polyendocrinopathy (AP). The close relationship between these two diseases is largely explained by sharing a common genetic background. The HLA antigens DQ2 (DQA1*0501-DQB1*0201) and DQ8 (DQA1*0301-DQB1*0302), tightly linked with DR3 and DR4, are the major common genetic predisposition. Moreover, functional single nucleotide polymorphisms (or rare variants) of various genes, such as the cytotoxic T-lym…

Regulatory changes in pterin and carotenoid genes underlie balanced color polymorphisms in the wall lizard

2019

Significance Reptiles show an amazing color diversity based on variation in melanins, carotenoids, and pterins. This study reveals genes controlling differences between three color morphs (white, orange, and yellow) in the common wall lizard. Orange pigmentation, due to high levels of orange/red pterins in skin, is caused by genetic changes in the sepiapterin reductase gene. Yellow skin, showing high levels of yellow carotenoids, is controlled by the beta-carotene oxygenase 2 locus. Thus, the color polymorphism in the common wall lizard is associated with changes in two small regions of the genome containing genes with crucial roles in pterin and carotenoid metabolism. These genes are likel…

Distinct bhaplotype structure at the innate immune receptor Toll-like receptor 2 across bank vole populations and lineages in Europe

2015

Abstract: Parasite-mediated selection may contribute to the maintenance of genetic variation at host immune genes over long time scales. To date, the best evidence for the long-term maintenance of immunogenetic variation in natural populations comes from studies on the major histocompatibility complex (MHC) genes, whereas evidence for such processes from other immune genes remains scarce. In the present study, we show that, despite pronounced population differentiation and the occurrence of numerous private alleles within populations, the innate immune gene Toll-like receptor 2 (TLR2) displays a distinct haplotype structure in 21 bank vole (Myodes glareolus) populations across Europe. Haplo…