家蚕保存系统红色卵的遗传分析

用遗传背景清楚的家蚕Bombyx mori红卵（re）、白卵(w-2、pe)、第4褐卵（b-4）的标志基因系统和正常型黑卵系统与我国家蚕基因库保存的20个红色卵系统杂交,进行顺反测验,分析了它们的卵色支配基因及遗传规律。结果发现：①在03-310系统中存在家蚕卵色新突变pink egg,与红卵re 等位,基因符号为re^p,表型特征为：卵淡红色,成虫蛾眼也为淡红色;②6个系统为红卵（re）的纯合系统,还有５个系统除具有re／re基因型外,还具有支配白色卵或浅红色或橙红色卵的突变基因;③２个系统为第4褐卵（b4）的纯合系统; ④6个系统的红褐色卵为母性影响遗传;⑤发现家蚕卵色基因b-4和r-e的互补关系,b-4/b-4 re/re基因型表现为新的卵色——橙黄色。     

Inheritance of seed color in Capsicum

The mode of seed color inheritance in Capsicum was studied via an interspecific hybridization between C. pubescens Ruiz and Pav. (black seed color) and C. eximium Hunz. (yellow seed color). Black seed color was dominant over yellow seed color. The F(2) segregation pattern showed continuous variation. The generation means analysis indicated the presence of a significant effect of additive [d], dominance [h], and additive x additive [i] interaction for seed color inheritance. The estimate for a minimum number of effective factors (genes) involved in seed color inheritance was approximately 3.     

Inheritance of flower color in chickpea

Flower color is a useful morphological marker in chickpea (Cicer arietinum L.). Inheritance of this trait was studied using two white-flowered chickpea genotypes, P 9623 and RS 11, and one blue-flowered genotype, T 39-1. The genetic constitutions of the white flower colors of P 9623 and RS 11 were different, for in an earlier study their F1 produced pink flowers. The two F1s of the crosses P 9623 x T 39-1 and RS 11 x T 39-1 also produced pink flowers. Each of the two F2 populations segregated in 9 pink:3 blue:4 white-flowered plants. These results can be explained by a three-gene model. These three independently segregating genes are probably the same as C, B, and P reported in the literature earlier. Allelic tests could not be undertaken, as the genetic stocks used in the earlier studies are not available. The genetic constitutions of the three parents and their F1s are proposed. These accessions should be useful for conducting allelic tests for determining flower color loci in chickpea and for comparative studies with field pea. The seeds of these genetic stocks are maintained at the Genetic Resources and Enhancement Program at ICRISAT and are available for research purposes on request.     

Inheritance of the harlequin color in Great Dane dogs

The harlequin color pattern of Great Dane dogs differs from merle in that the background is white instead of blue. Harlequin by harlequin matings produced 60 black, 77 harlequin, 42 merle, and 35 homozygous merle pups. Harlequin by black matings produced 44 black, 26 harlequin, 25 merle, and one white (homozygous merle?) pups. All harlequins produced some merles. These data best fit the hypothesis that harlequin is a modification of merle (Mm) caused by an autosomal dominant mutation that is lethal to homozygotes, and to about half of heterozygotes when combined with the MM genotype. The symbol H is proposed for this mutation.     

Inheritance of color and horns in blue-gray cattle

Ohne Zusammenfassung     

Inheritance of body color in the brown planthopper, Nilaparvata lugens

The segregation frequencies of color phenotypes of F₁, F₂, and backcross progenies revealed that the body coloration of the brown planthopper, Nilaparavata lugens(Stål), exhibited multiple allelism. Monogene for color morphism exists in three allelic forms >-b ⁺ (brown or wild type), b ^o (orange) and b ^b (black). The dominance relationship was b ^b>b ⁺>b ^o. The relationship between phenotype and genotype in N. lugens was not fixed. The six possible genotypes produced eight phenotypes.

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Résumé Les fréquences de ségrégation des différentes colorations de F₁, F₂ et des croisements en retour ont montré que la coloration du corps de Nilaparvata lugens est due à un multi-allèlisme. Le monogène pour la couleur existe sous trois formes allèliques: b⁺ (brun ou sauvage), b^o (orange) et b^b (noir). Les relations de dominance étaient: b^b>b⁺>b^o. On n'a pas établi les relatios entre phénotypes et génotypes chez N. lugens. Les 6 génotypes possibles produisent 8 phénotypes.

     

Introgressive hybridization of tilapias in Zimbabwe

Three species of tilapia native to Zimbabwe, Oreochromis mossambicus, O. mortimeri and O. macrochir are not naturally sympatric, but because of transplantation they have been brought into sympatry. Allozymes of fish examined from Lakes Kariba, Kyle and Chivero showed evidence of introgressive hybridization. The data showed non-random mating populations in Lakes Kariba and Kyle. All three reservoirs displayed individuals with intermediate principal component scores and hybrid index scores indicating hybridization.     

Inheritance of a Lutescent-Leaf color trait in peanut.

A Lutescent-Leaf color mutant was recently found in the cultivated peanut (Arachis hypogaea L.). Crosses involving the Lutescent-Leaf mutant were made both between and within subspecies of hypogaea and fastigiata to determine its inheritance. The F1, F2, and F3 data indicated that two duplicate recessive genes, designated lut1 and lut2, control the Lutescent-Leaf color trait. No maternal or cytoplasmic effects were detected among progenies from reciprocal hybridization.     

Inheritance of the snakeskin color pattern in the guppy, Poecilia reticulata

We made single-pair reciprocal crosses between the Green Snakeskin and Yellow Snakeskin domesticated strains of the guppy, Poecilia reticulata. The two snakeskin strains differ by a single autosomal gene, with the Green Snakeskin strain having the wild-type background coloration caused by the dominant gene (B), whereas the Yellow Snakeskin is homozygous for the recessive blond allele (bb). The snakeskin body and tail patterns characterizing males of these two strains are determined by two genes--Ssb and Sst--that are closely linked on the Y chromosome. The greenish-yellow tail color of the Green Snakeskin strain is mediated by an X-linked dominant gene, Grt. The recessive wild-type allele, Grt+, gives the hyaline tail color. In the Yellow Snakeskin strain, the Grt gene is expressed as a golden-yellow color as a result of the presence of the bb homozygous condition. The putative genotypes of the males and females of the Green Snakeskin strain are BB XGrt YSsb,Sst and BB XGrt XGrt, respectively. Males and females of the Yellow Snakeskin strain have the putative genotypes bb XGrt YSsb,Sst and bb XGrtXGrt, respectively. As a result of crossing over between the X and Y chromosomes, a few males and females of these two snakeskin strains may carry one or both snakeskin pattern genes (Ssb and Sst) on the X chromosome.     

Seeing red: color vision in the largemouth bass

How animals visually perceive the environment is key to understanding important ecological behaviors, such as predation, foraging, and mating. This study focuses on the visual system properties and visual perception of color in the largemouth bass Micropterus salmoides. This study (1) documents the number and spectral sensitivity of photoreceptors,(2) uses these parameters to model visual perception, and (3) tests the model of color perception using a behavioral assay. Bass possess single cone cells maximally sensitive at 535 nm, twin cone cells maximally sensitive at 614 nm, and rod cells maximally sensitive at 528 nm. A simple model of visual perception predicted that bass should not be able to discern between chartreuse yellow and white nor between green and blue. In contrast, bass should be able to discern red from all achromatic (i.e., gray scale) stimuli. These predictions were partially upheld in behavioral trials. In behavioral trials, bass were first trained to recognize a target color to receive a food reward, and then tested on their ability to differentiate between their target color and a color similar in brightness. Bass trained to red and green could easily discern their training color from all other colors for target colors that were similar in brightness (white and black, respectively). This study shows that bass possess dichromatic vision and do use chromatic (i.e., color) cues in making visual-based decisions.     

Myxosporean infections in cultured tilapias in Israel

Five new species of myxosporean parasite are described from cultured tilapias in Israel. These are: Myxosoma sarigi, Myxosoma equatorialis, Myxobolus israelensis, Myxobolus agolus, and Myxobolus galilaeus. The first four were found in hybrids of Oreochromis aureus X Oreochromis niloticus while Myxobolus galilaeus was found in Sarotherodon galilaeus. In addition, M. sarigi, M. israelensis, and Myxobolus sp. were also found in S. galilaeus. In the light of the present study, the taxonomy of myxosporean infections in tilapias is modified. Mature spores may localize in the melano-macrophage centers of the spleen and kidney where they may eventually be destroyed. No cases of mortality have so far been associated with these parasites.     

Inheritance of coat color in the mole vole (Ellobius talpinus Pallas)

Based on the ecological features of the mole vole, family analysis of the inheritance of coat color was performed with the use of material collected in a wild population. Analysis of coat color in parents and offspring has demonstrated that the offspring segregation into black and nonblack animals after crosses of different types agrees with the hypothesis on the monogenic inheritance of these color variations. Black mole voles are homozygous for the recessive allele (genotype aa). Homozygotes for the dominant allele (AA) are brown. Heterozygotes (Aa) may be brown or have transitional color. The mean frequency of brown coat color in heterozygotes is 0.509 and is very variable. The higher the color intensity in black elements of parent coat color, the more is the offspring coat color saturated with these elements.     

Inheritance of flower color in pickerelweed (Pontederia cordata L.)

Pickerelweed (Pontederia cordata L.) is a diploid (2n = 2x = 16), erect, emergent, herbaceous aquatic perennial. The showy inflorescences of pickerelweed make this species a prime candidate for inclusion in water gardens and aquascapes. The objective of this experiment was to determine the number of loci, number of alleles, and gene action controlling flower color (blue vs. white) in pickerelweed. Two blue-flowered and one white-flowered parental lines were used in this experiment to create S(1) and F(1) populations. F(2) populations were produced through self-pollination of F(1) plants. Evaluation of S(1), F(1), and F(2) generations revealed that flower color in these populations was controlled by 2 alleles at one locus with blue flower color completely dominant to white. We propose that this locus be named white flower with alleles W and w.     

Inheritance and QTL analysis of the determinants of flower color in tetraploid cut roses

The success of cut rose cultivars is a direct result of their aesthetic value. The rose industry thrives on novelty, and the production of novel flower color has been extensively studied. The most popular color is red, and it is, therefore, important for breeders to produce a good red cultivar. The final visible color of the flower is a combination of a number of factors including the type of anthocyanin accumulating, modifications to the anthocyanidin molecule, co-pigmentation and vacuolar pH. Here, we analyze the quantitative variation of the biochemical constituents of flower color in a tetraploid rose population and combine this with marker information in the segregating rose population to map the chromosomal locations of putative QTLs for flower color traits. Within our tetraploid population, we found a number of QTLs that were mapped on ICM 1, 2, 6 and 7. We were able to show the effect of the different QTLs on the final visible color of the flower from salmon to dark red.