Genetic Variation in Released Gametes Produces Genetic Diversity in the Offspring of the Broadcast Spawning Coral Acropora Tenuis

2021 ◽  
Author(s):  
Seiya Kitanobo ◽  
Sho Toshino ◽  
Masaya Morita
Keyword(s):  
Genetic Diversity ◽  
Coral Species ◽  
Sperm Concentration ◽  
Peak Height ◽  
Fertilization Success ◽  
High Fecundity ◽  
Broadcast Spawning ◽  
Fragment Peak ◽  
Acropora Tenuis

Abstract All coral species in the genus Acropora are broadcast-spawning hermaphrodites. Fertilization in the ocean requires sufficient numbers of gametes from conspecifics and the contact time for fertilization is thought to be limited by the rapid diffusion of sperm. Many studies have reported a positive correlation between sperm concentration and fertilization success, but it is not clear how released gametes are fertilized in nature (in situ) and how genetic diversity arises at a fertilization event. To elucidate this, we analyzed the changes in sperm concentration in situ after spawning and genotyped sperm and fertilized eggs from seawater using seven microsatellite (MS) markers. This showed that the sperm concentration in situ was suboptimal (<106 sperm/mL), but most of the eggs were fertilized. MS genotyping showed that the alleles of released sperm were diverse and those alleles also appeared in the fertilized eggs. In addition, the MS fragment peak height in released sperm, which presumable reflects the allele frequency of the sperm, was positively correlated with the allele frequencies of the fertilized eggs. Collectively, the genetic diversity of colonies with high fecundity dictates the genetic diversity of their descendants.

Genetic diversity of the extremely rare Habenaria dentata and the rare Habenaria linearifolia (Orchidaceae) in South Korea: implications for population history and conservation

2018 ◽  
Vol 151 (1) ◽  
pp. 48-60
Author(s):  
Mi Yoon Chung ◽  
Hoa Thi Quynh Le ◽  
Sungwon Son ◽  
Huai Zhen Tian ◽  
Myong Gi Chung
Keyword(s):  
Genetic Diversity ◽  
Southern China ◽  
Geographic Location ◽  
Population History ◽  
Population Variation ◽  
Conservation Strategies ◽  
Ancestral Population ◽  
Allozyme Diversity ◽  
Glacial Origin

Background and aims – Since historical events often leave an indelible mark on levels of genetic diversity of plant populations, one may indirectly infer their evolutionary history with the help of current patterns of genetic diversity. The terrestrial orchid Habenaria dentata, an element of warm-temperate/subtropical vegetation, reaches its northernmost limits in the Korean Peninsula, and thus it is extremely rare there. As H. dentata was absent from the Peninsula during the Last Glacial Maximum (LGM), it is likely to be of post-glacial origin having arrived from either a single refugium or multiple refugia. However, its rare, temperate/boreal congener H. linearifolia might have persisted in situ in either macrorefugia or microrefugia on the Peninsula during the LGM.Methods – To test which hypothesis is most appropriate for each species, we investigated levels of allozyme-based (17 loci) genetic diversity and population genetic structure in the two only known populations of H. dentata and in 12 populations of H. linearifolia.Key results – No allozyme diversity was found in H. dentata (He = 0.000), whereas H. linearifolia exhibited low within-population variation (He = 0.060) and high among-population differentiation (FST = 0.237). We found little association between populations in relation to their geographic location; several populations presented individuals belonging to different clusters.Conclusions – Our results suggest that H. dentata likely originated from a single ancestral population (perhaps from southern Japan or southern China) through post-glacial dispersal, whereas H. linearifolia probably survived the LGM in situ in microrefugia situated at low to mid-elevated regions. We further suggest that separate conservation strategies for each species should be employed, given that the two taxa have different ecological and demographic traits and harbour different levels of genetic diversity.

Impaired Testicular Function in Patients With Carcinoma-In-Situ of the Testis

1999 ◽  
Vol 17 (1) ◽  
pp. 173-173 ◽  
Author(s):  
Peter Meidahl Petersen ◽  
Aleksander Giwercman ◽  
Steen W. Hansen ◽  
Jørgen G. Berthelsen ◽  
Gedske Daugaard ◽  
...  
Keyword(s):  
Testicular Cancer ◽  
Germ Cell ◽  
Leydig Cell ◽  
Carcinoma In Situ ◽  
Cell Function ◽  
Semen Quality ◽  
Sperm Concentration ◽  
Testicular Dysfunction ◽  
Leydig Cell Function

PURPOSE: To elucidate the biologic association between germ cell neoplasia and testicular dysfunction, through investigation of Leydig cell function and semen quality in men with carcinoma-in-situ (CIS) of the testis. PATIENTS AND METHODS: We examined two groups of men, unilaterally orchidectomized for testicular cancer. Biopsy of the contralateral testis had showed CIS in a group of 24 patients and no evidence of CIS in the other group of 30 patients. Semen quality and serum levels of testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were compared in these two groups of men after orchidectomy but before further treatment for testicular cancer. RESULTS: Significantly higher LH levels (median, 8.1 IU/L v 4.8 IU/L; P < .001) and generally lower testosterone levels (median, 12.5 nmol/L v 15.5 nmol/L; P = .13) were found in the CIS group. The proportion of patients with Leydig cell dysfunction was higher in the group of patients with CIS (11 of 24) than in the group of patients without (two of 30) (P = .01). Sperm concentration and total sperm count were significantly lower (P < .001) in patients with CIS (median, 0.03 × 106/mL and 0.10 × 106, respectively) than in patients without (median, 9.1 × 106/mL and 32 × 106, respectively), whereas the levels of FSH were significantly higher (P < .001) in the former group of men (median, 19.6 IU/L v 9.0 IU/L). CONCLUSION: Not only spermatogenesis but also Leydig cell function is impaired in testes with CIS. This impairment could be due to common factors in the pathogenesis of germ cell neoplasm and testicular dysfunction. Alternatively, CIS cells may have a negative impact on Leydig cell function.

Overt and Concealed Genetic Loads Revealed by QTL Mapping of Genotype-dependent Viability in the Pacific Oyster Crassostrea gigas

Genetics ◽  
2021 ◽  
Author(s):  
Xiaoshen Yin ◽  
Dennis Hedgecock
Keyword(s):  
Genetic Diversity ◽  
Crassostrea Gigas ◽  
Pacific Oyster ◽  
Genetic Load ◽  
High Density ◽  
High Genetic Diversity ◽  
High Fecundity ◽  
Recessive Mutations ◽  
Genotype Frequencies ◽  
The Pacific

Abstract Understanding the genetic bases of inbreeding depression, heterosis, and genetic load is integral to understanding how genetic diversity is maintained in natural populations. The Pacific oyster Crassostrea gigas, like many long-lived plants, has high fecundity and high early mortality (type-III survivorship), manifesting a large, overt, genetic load; the oyster harbors an even greater concealed genetic load revealed by inbreeding. Here, we map viability QTL (vQTL) in six interrelated F2 oyster families, using high-density linkage maps of single nucleotide polymorphisms generated by genotyping-by-sequencing (GBS) methods. Altogether, we detect 70 vQTL and provisionally infer 89 causal mutations, 11 to 20 per family. Genetic mortality caused by independent (unlinked) vQTL ranges from 94.2% to 97.8% across families, consistent with previous reports. High-density maps provide better resolution of genetic mechanisms, however. Models of one causal mutation present in both identical-by-descent (IBD) homozygotes and heterozygotes fit genotype frequencies at 37 vQTL; consistent with the mutation-selection balance theory of genetic load, 20 are highly deleterious, completely recessive mutations and 17 are less deleterious, partially dominant mutations. Another 22 vQTL require pairs of recessive or partially dominant causal mutations, half showing selection against recessive mutations linked in repulsion, producing pseudo-overdominance. Only eight vQTL appear to support the overdominance theory of genetic load, with deficiencies of both IBD homozygotes, but at least four of these are likely caused by pseudo-overdominance. Evidence for epistasis is absent. A high mutation rate, random genetic drift, and pseudo-overdominance may explain both the oyster’s extremely high genetic diversity and a high genetic load maintained primarily by mutation-selection balance.

scholarly journals Coralivoría del gasterópodo Jenneria pustulata (Ovulidae: Pediculariinae) en dos arrecifes coralinos del PNN isla Gorgona

2018 ◽  
Vol 47 (2) ◽  
Author(s):  
Mauro Giovanni Zucconi ◽  
Levy D. Obonaga ◽  
Edgardo Londoño-Cruz
Keyword(s):  
Coral Reefs ◽  
Coral Species ◽  
Size Structure ◽  
Coral Tissue ◽  
Laboratory Conditions ◽  
Set Up ◽  
Biological Dynamics ◽  
Colombian Pacific

Coral reefs are very important and highly biodiverse ecosystems that are exposed to various stressors, including biological ones, such as parasitism and corallivory – the direct consumption of coral tissue by a predator. Knowledge on the effects of corallivory on the coral reefs in the Colombian Pacific is poor. Therefore a study was set up to quantify the abundance of and the corallivory rate by the snail Jenneria pustulata in La Azufrada and Playa Blanca coral reefs (Gorgona Island, Colombia). Snails were manually sampled from the underside of Pocillopora sp. colonies and measured in situ to determine their size structure for each reef. To measure possible damage caused by corallivory, several snails were kept under controlled laboratory conditions for 24 h. Snail sizes and corallivory varied significantly between reefs (P=0.0001; P«0.001). Snails from Playa Blanca were larger than snails from La Azufrada, while corallivory was higher in La Azufrada than in Playa Blanca. Although corallivory rates by J. pustulata are smaller than rates reported for other predators in different coral species, it is recommended to continue this kind of investigations in order to increase the knowledge on biological dynamics of this species and to understand how they affect the reefs at Gorgona Island.

scholarly journals AUTOCHTHONOUS BREEDS OF DOMESTIC ANIMALS AND CONSERVATION MEASURES

AGROFOR ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Zoran MALETIC
Keyword(s):  
Genetic Diversity ◽  
Biological Diversity ◽  
Domestic Animals ◽  
Conservation Strategy ◽  
Ex Situ ◽  
Animal Genetic Resources ◽  
Diversity Preservation ◽  
The Republic ◽  
International Conventions

Recently, highly productive breeds of various species of domestic animals have been used in livestock production, which has resulted in the destruction of indigenous breeds of domestic animals around the world, even in our area. This is the first reason why indigenous races and strains have been endangered. Another reason is that domestic, indigenous breeds were crossed with specialized breeds, which were imported, and in that way their genetic diversity was negatively affected. Resistance is lost, adaptation to the conditions in which they were created, the ability to survive in nature. Indigenous breeds of different species of domestic animals, which are recognized in the Republic of Srpska (BiH) are gatačko cattle and buša (cattle), Vlašić pramenka, Podveleška pramenka, Kupres pramenka (sheep), domestic Balkan horned goat (goats), Bosnian mountain horse (horses), mangulica (pigs) and pogrmuša hen or živičarka hen (poultry). By acceding to international conventions, BiH /Republic of Srpska has committed itself to establishing a system of measures that will enable the conservation of biological diversity and the protection of indigenous and endangered breeds of domestic animals. The choice of a strategy for the conservation of diversity, the establishment of an adequate conservation scheme, and the implementation of a conservation strategy are some of the key elements of any process for the conservation of genetic diversity. Preservation of autochthonous and protected breeds of domestic animals is possible through preservation in the original environment (in situ) and preservation outside the original environment (ex situ). There is a possibility of combining these models of conservation of animal genetic resources.

scholarly journals Canine bocavirus-2 infection and its possible association with encephalopathy in domestic dogs

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255425
Author(s):  
Chutchai Piewbang ◽  
Sabrina Wahyu Wardhani ◽  
Wichan Dankaona ◽  
Sitthichok Lacharoje ◽  
Poowadon Chai-in ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Control Group ◽  
Normal Brain ◽  
Evolutionary Analysis ◽  
Histological Changes ◽  
Brain Infection ◽  
Transmission Electron ◽  
Viral Particles ◽  
Cellular Tropism

Canine bocaviruses (CBoVs) have been recognized as pathogens associated with intestinal diseases. Hematogenous spreading caused by CBoV has been documented and may potentiate the virus entry across the blood-brain barrier to initiate a brain infection. This study focused attention on CBoV detection in cases of encepahlopathy and attempted to determine its viral localization. A total of 107 dog brains that histologically exhibited encephalopathy (ED) were investigated for the presence of CBoVs using polymerase chain reaction (PCR). Thirty-three histologically normal brain samples from dogs were used as a control group (CD). CBoV-2 was detected in 15 ED dogs (14.02%) but not in CD dogs (p = 0.02), while no CBoV-1 and -3 were detected. Among the CBoV-2 positive dogs, brain histological changes were characterized by nonsuppurative encephalitis, with inclusion body-like materials in some brains. In situ hybridization (ISH) and transmission electron microscopy (TEM) confirmed the presence of CBoV-2 viral particles in glial cells, supporting neurotropism of this virus. ISH signals were also detected in the intestines, lymphoid organs, and the heart, suggesting both enteral and parenteral infections of this virus. Whole genome characterization and evolutionary analysis revealed genetic diversity of CBoV-2 sequences and it was varying among the different countries where the virus was detected. This study points to a possible association of CBoV-2 with encephalopathy in dogs. It also highlights the genetic diversity and cellular tropism of this virus.

Ecological Distribution, Agricultural Trade Liberalization, and IN SITU Genetic Diversity

1997 ◽  
Author(s):  
J. Boyce
Keyword(s):  
Genetic Diversity ◽  
Rural Livelihoods ◽  
Agricultural Trade ◽  
Costs And Benefits ◽  
The North ◽  
Agricultural Trade Liberalization ◽  
Agricultural Imports ◽  
World Food Security

Genetic diversity in crop plants is crucial for long-term world food security. This diversity is sustained in the field primarily by poor farmers in developing countries, who receive no compensation for providing this external benefit to humankind. When agricultural imports displace local production in centers of genetic diversity, this threatens both rural livelihoods and the continued provision of this external benefit. The North American Free Trade Agreement’s impact on Mexican maize farming illustrates the problem. The prospects for remedial policies are shaped by the distribution of the costs and benefits of action of inaction.

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