The Breeding Evidence Indicating Two Genetic Types of Females of Ips tridens Mannerheim) (Coleoptera: Scolytidae)

1964 ◽  
Vol 96 (1-2) ◽  
pp. 117-118 ◽  
Author(s):  
G. R. Hopping
Keyword(s):  
Sex Ratio ◽  
Related Species ◽  
Mortality Factor ◽  
Unexpected Result ◽  
Closely Related Species ◽  
Inner Bark ◽  
Genetic Types ◽  
Stage Of Development ◽  
Gallery System ◽  
Entrance Hole

Members of the genus Ips are polygamous. The male excavates the entrance hole and a small nuptial chamber between the inner bark and sapwood. The females then enter and each excavates an egg gallery starting from the nuptial chamber. The number of females per gallery system ranges from 1 to 5 but the most common number is 3. This sex ratio of approximately 3 ♀ ♀: 1 ♂ has been attributed to some mortality factor more lethal to the males in some stage of development. Breeding of isolated pairs under laboratory conditions was carried out primarily to determine the variability between individuals from the same brood and between individuals from different broods. The objective was to resolve the complex of closely related species in the Ips tridens–I. engelmanni group. An unexpected result was a clarification of the sex ratio problem.

scholarly journals Revisiting suppression of interspecies hybrid male lethality in Caenorhabditis nematodes

2017 ◽  
Author(s):  
Lauren E. Ryan ◽  
Eric S. Haag
Keyword(s):  
Rna Interference ◽  
Sex Ratio ◽  
Related Species ◽  
Wild Type ◽  
Hybrid Male ◽  
Female Progeny ◽  
Closely Related Species ◽  
Interspecies Hybrids ◽  
Biased Sex Ratio ◽  
Interspecies Hybrid

AbstractWithin the nematode genus Caenorhabditis, C. briggsae and C. nigoni are among the most closely related species known. They differ in sexual mode, with C. nigoni retaining the ancestral XO male-XX female outcrossing system, while C. briggsae females recently evolved self-fertility and an XX-biased sex ratio. Wild-type C. briggsae and C. nigoni can produce fertile hybrid XX female progeny, but XO progeny are either 100% inviable (when C. briggsae is the mother) or viable but sterile (when C. nigoni is the mother). A recent study provided evidence suggesting that loss of the Cbr-him-8 meiotic regulator in C. briggsae hermaphrodites allowed them to produce viable and fertile hybrid XO male progeny when mated to C. nigoni. Because such males would be useful for a variety of genetic experiments, we sought to verify this result. Preliminary crosses with wild-type C. briggsae hermaphrodites occasionally produced fertile males, but they could not be confirmed to be interspecies hybrids. Using an RNA interference protocol that eliminates any possibility of self-progeny in Cbr-him-8 hermaphrodites, we find sterile males bearing the C. nigoni X chromosome, but no fertile males bearing the C. briggsae X, as in wild-type crosses. Our results suggest that the apparent rescue of XO hybrid viability and fertility is due to incomplete purging of self-sperm prior to mating.

Comparative AFLP reveals paternal sex ratio chromosome specific DNA sequences in the parasitoid wasp Trichogramma kaykai

Genome ◽  
2009 ◽  
Vol 52 (5) ◽  
pp. 447-455
Author(s):  
Joke J.F.A. van Vugt ◽  
Ron G.M. van der Hulst ◽  
Andrea J.P. Pruijssers ◽  
Patrick Verbaarschot ◽  
Richard Stouthamer ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Dna Sequences ◽  
Related Species ◽  
Parasitoid Wasp ◽  
Specific Marker ◽  
Paternal Genome ◽  
Closely Related Species ◽  
Repetitive Nature ◽  
Aflp Fragment ◽  
Paternal Sex Ratio

The parasitoid wasp Trichogramma kaykai with a haplo-diploid sex determination has a B chromosome called the paternal sex ratio (PSR) chromosome that confers paternal genome loss during early embryogenesis, resulting in male offspring. So far, it is not well known whether the PSR chromosome has unique DNA sequence characteristics. By comparative AFLP fingerprinting of genomic DNA from wasps with and without the PSR chromosome, we isolated DNA from PSR-specific bands. Fourteen of such DNA fragments were analysed to confirm their PSR specificity. Seven were sequenced and two (PT-AFLP 1 and PT-AFLP1 3) were identified as parts of retrotransposon genes based on BLAST searches. Internal primers designed from a third AFLP fragment allowed PCR amplification of a PSR chromosome specific marker, which can be used to screen for the PSR trait in male wasps. Southern analysis revealed a dispersed repetitive nature of this third sequence in the T. kaykai genome, suggesting that it is part of a transposon. A fourth AFLP fragment (PT-AFLP 5) appears to be a large repetitive sequence on the PSR chromosome. This sequence is also found in the genome of both T. kaykai and the closely related species Trichogramma deion , but its distribution on the PSR chromosome strongly resembles that of T. deion rather than that of T. kaykai. Our results provide further insight into the repetitive nature of sequences comprising B chromosomes and their similarities with their host and closely related species.

A Method of Rearing Bark- and Cambium-Feeding Beetles with particular Reference to Hylobius warreni Wood (Coleoptera: Curculionidae)

1958 ◽  
Vol 90 (7) ◽  
pp. 425-428 ◽  
Author(s):  
G. L. Warren
Keyword(s):  
Life History ◽  
Root System ◽  
Related Species ◽  
Jack Pine ◽  
Closely Related Species ◽  
Inner Bark ◽  
History Of ◽  
Biological Differences

Hylobius warreni Wood is a recently described weevil that was originally confused with Hypomolyx piceus (DeGeer, 1957). The larvae attack the inner bark and cambium of the root system of jack pine, Pinus bankisiana Lamb., and other conifers (Warren, 1956). The life history of this insect is being studied to determine biological differences between it and a closely related species, Hylobius pinicola (Couper). This information is also essential in order to continue detailed studies on the effect of site and other factors on the abundance of H. warreni (Warren, 1956a). The first requirement for fulfilling these objectives is the development of a satisfactory rearing technique.

Microsatellite Marker: Importance and Implications of Cross-genome Analysis for Finger Millet (Eleusine coracana (L.) Gaertn)

2020 ◽  
Vol 9 (3) ◽  
pp. 160-170
Author(s):  
Thumadath P.A. Krishna ◽  
Maharajan Theivanayagam ◽  
Gurusunathan V. Roch ◽  
Veeramuthu Duraipandiyan ◽  
Savarimuthu Ignacimuthu
Keyword(s):  
Molecular Marker ◽  
Microsatellite Markers ◽  
Ssr Markers ◽  
Genome Analysis ◽  
Related Species ◽  
Finger Millet ◽  
Crop Improvement ◽  
Human Beings ◽  
Closely Related Species ◽  
Genome Amplification

Finger millet is a superior staple food for human beings. Microsatellite or Simple Sequence Repeat (SSR) marker is a powerful tool for genetic mapping, diversity analysis and plant breeding. In finger millet, microsatellites show a higher level of polymorphism than other molecular marker systems. The identification and development of microsatellite markers are extremely expensive and time-consuming. Only less than 50% of SSR markers have been developed from microsatellite sequences for finger millet. Therefore, it is important to transfer SSR markers developed for related species/genus to finger millet. Cross-genome transferability is the easiest and cheapest method to develop SSR markers. Many comparative mapping studies using microsatellite markers clearly revealed the presence of synteny within the genomes of closely related species/ genus. Sufficient homology exists among several crop plant genomes in the sequences flanking the SSR loci. Thus, the SSR markers are beneficial to amplify the target regions in the finger millet genome. Many SSR markers were used for the analysis of cross-genome amplification in various plants such as Setaria italica, Pennisetum glaucum, Oryza sativa, Triticum aestivum, Zea mays and Hordeum vulgare. However, there is very little information available about cross-genome amplification of these markers in finger millet. The only limited report is available for the utilization of cross-genome amplified microsatellite markers in genetic analysis, gene mapping and other applications in finger millet. This review highlights the importance and implication of microsatellite markers such as genomic SSR (gSSR) and Expressed Sequence Tag (EST)-SSR in cross-genome analysis in finger millet. Nowadays, crop improvement has been one of the major priority areas of research in agriculture. The genome assisted breeding and genetic engineering plays a very crucial role in enhancing crop productivity. The rapid advance in molecular marker technology is helpful for crop improvement. Therefore, this review will be very helpful to the researchers for understanding the importance and implication of SSR markers in closely related species.

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