• Journal of Forest and Environmental Science
• /
• 제31권3호
• /
• pp.164-176
• /
• 2015

Cyathea gigantea is a tree fern distributed throughout humid tropical regions of northeast India and other parts of the country. However, wild populations of this species are largely affected by various natural and anthropogenic activities. Therefore, an attempt was made to study the population structure and regeneration status of C. gigantea in and around greater Itanagar area of Papum Pare district, Arunachal Pradesh. Altogether 45 patches, ranging from 19.63 to $260m^2$ of area, were randomly sampled to study population structure and regeneration status of the species. Population study showed highest number of youngs in the height class of 0.50-0.75 m while, immatures were recorded highest in the height class of 2.0 to 2.5 m. Majority of the matures belonged to 6-9 m height class while it was recorded maximum in the diameter class of 10-15 cm. Average density of C. gigantea was $0.07individuals\;ha^{-1}$ which varied greatly among different patches with a range of 2 to 14. Significant correlations were found between patch size and density of youngs, immatures, matures and total density. Maximum concentration of youngs was observed in patch size $60-140m^2$, while for immatures, it was highest in patch size $20-160m^2$. Similarly, highest concentration of matures was observed in patch size $20-80m^2$ and $80-180m^2$. Population structure of the total population exhibited inverted pyramid shaped distribution. Population structure consisting of youngs, immatures, matures showed that around 60% patches lack of regenerating individuals which depict very poor natural regeneration of the species. Effective conservation strategies are therefore to be formulated to save C. gigantea from the threat of extinction in near future.

• 수산해양기술연구
• /
• 제46권4호
• /
• pp.392-405
• /
• 2010

The population of small yellow croaker, Larimichthys polyactis, in the Yellow and East China Seas has decreased significantly since the mid 1970s. Several management measures have been introduced to conserve it, but population size remains low. To rebuild this population, it is now necessary to consider more effective management methods based on the stock assessment. To determine long-term population changes, fishery and biological data collected over 34 years (1969-2002) were analysed. Yearly fish length compositions were analysed for the time periods 1968 through 1970, 1978 through 1982, and 1993 through 2002; and catch data was available from 1969 to 2002. Annual population sizes were calculated based on length composition, the relationship between total length and body weight, and total landings. Analyses showed that since the 1970s, average size of harvested fish decreased; the proportion of less mature fish (smaller than the 50% maturity length, 19cm) in catches has increased and the estimated biomass has decreased significantly. Consequently, the main management recommendation is that juvenile fish need to be better protected to allow the rebuilding of resources to a more sustainable population level. This will require fish size limit, permissible mesh size, and closed area and season regulations.

• 생명과학회지
• /
• 제13권3호
• /
• pp.252-257
• /
• 2003

인가성 종인 노랑 초파리의 제2염색체를 대상으로, 자연집단과 장기 유지시켜온 실험집단의 생존도 관련 유해유전자의 빈도를 조사하였다. 2년간 연속 조사한 부산 일원 자연집단내의 치사 및 반치사를 포함한 유해유전자의 빈도는 약 14.3∼25.4% 정도로서 년도 의존적 불안정 변이를 보인 반면 집단 형성 후 약 6570일과 약 7300일째의 실험집단내의 동 빈도는 약 26.5∼27.2% 정도로서 매우 안정적인 변이를 나타내고 있었다. 치사유전자 보유 염색체를 대상으로한 동좌율 조사에서는 자연집단에서 0.76%의 낮은 비율인데 반하여 실험집단에서는 9.76∼14.17%의 높은 동좌 비율을 보였다. 완전 정상 유전자 보유 계통만으로 형성, 장기 유지시켜온 실험집단내의 치사유전자의 유발과 축적은 세대를 거듭함에 따라 자연 돌연변이에 의해 6570일 현재 약 14.5%의 안정적 빈도를 보여주었다. 집단 내 치사 유전자의 동형접합체화로 인한 집단 내에서의 제거율은 6570일 현재 약 0.0106 정도이며, 이로부터 환산되는 실험집단내의 유효크기는 약 430개체 정도였다.

• Animal Bioscience
• /
• 제37권5호
• /
• pp.795-806
• /
• 2024

Objective: Karan Fries (KF), a high-producing composite cattle was developed through crossing indicine Tharparkar cows with taurine bulls (Holstein Friesian, Brown Swiss, and Jersey), to increase the milk yield across India. This composite cattle population must maintain sufficient genetic diversity for long-term development and breed improvement in the coming years. The level of linkage disequilibrium (LD) measures the influence of population genetic forces on the genomic structure and provides insights into the evolutionary history of populations, while the decay of LD is important in understanding the limits of genome-wide association studies for a population. Effective population size (N_e) which is genomically based on LD accumulated over the course of previous generations, is a valuable tool for e valuation of the genetic diversity and level of inbreeding. The present study was undertaken to understand KF population dynamics through the estimation of N_e and LD for the long-term sustainability of these breeds. Methods: The present study included 96 KF samples genotyped using Illumina HDBovine array to estimate the effective population and examine the LD pattern. The genotype data were also obtained for other crossbreds (Santa Gertrudis, Brangus, and Beefmaster) and Holstein Friesian cattle for comparison purposes. Results: The average LD between single nucleotide polymorphisms (SNPs) was r² = 0.13 in the present study. LD decay (r² = 0.2) was observed at 40 kb inter-marker distance, indicating a panel with 62,765 SNPs was sufficient for genomic breeding value estimation in KF cattle. The pedigree-based N_e of KF was determined to be 78, while the N_e estimates obtained using LD-based methods were 52 (SNeP) and 219 (genetic optimization for N_e estimation), respectively. Conclusion: KF cattle have an N_e exceeding the FAO's minimum recommended level of 50, which was desirable. The study also revealed significant population dynamics of KF cattle and increased our understanding of devising suitable breeding strategies for long-term sustainable development.

• Journal of Animal Science and Technology
• /
• 제55권5호
• /
• pp.367-371
• /
• 2013

본 연구는 우리나라 Holstein 젖소의 혈통정보를 이용하여 근교계수 및 유효집단크기를 추정하여, 우리나라 Holstein 집단의 문제점을 진단하고, 대처방안을 모색하고자 실시하였다. 분석에 사용된 자료는 (사)한국종축개량협회에 등록된 젖소 중 기초등록을 제외한 635,268두의 자료를 이용하였다. 평균 근교계수는 0.11에서 1.07%의 범위를 나타내었는데, 13세대까지는 비슷한 수준을 유지하다가 14세대 (0.43%)부터 증가하기 시작하여, 19세대에는 0.92%, 22세대에는 1.07%로 증가되었다. 근교계수가 0%, 0~6.25%, 6.25~12.5%, 12.50~25.% 및 25.% 이상인 개체의 비율은 각각 50.5%, 48.3%, 0.8%, 0.1% 및 0.3%로 나타났다. 유효집단 크기는 8세대부터 22세대까지 및 19세대부터 22세대까지에서 각각 619두 및 922두로 추정되었다.

• 농업과학연구
• /
• 제44권4호
• /
• pp.549-557
• /
• 2017

As exchanges between countries become more active, new threats such as drugs, illegal imports of food and medicines, and terrorism are present all over the world. From this, increased border security that protects people's safety is becoming a new issue. The activities of special purpose dogs that detect these threats in advance are becoming very important. One of the obstacles in securing superior individuals is musculoskeletal disorders which interfere with the work of special purpose dogs. In order to search for genes associated with these genetic disorders, we conducted genomic analysis using linkage disequilibrium information and investigated genetic characteristics to know heterozygosity and inbreeding status in the population. In this study, two breeds (Malinois, Shepherd) of army dogs and three breeds (Malinois, Shepherd, Retriever) from public databases were used for comparison. The 170K SNP marker panel was used for this study. In the principal component analysis, it was confirmed that clusters were formed for each breed. The number of effective populations differed for each cultivar, but this was due to the difference in numbers of individuals for each breed used for the analysis. The results of heterozygosity decay analysis showed that heterozygous alleles decreased with each generation. In the army dog group, if the population number is maintained properly, the frequency of allele genotype will not decrease significantly.

• 대한예방의학회:학술대회논문집
• /
• 대한예방의학회 2003년도 제11회 춘계 심포지움 연제집
• /
• pp.30-37
• /
• 2003

o Cohort study became the major approach to study of chronic diseases such as CVD and cancer o Cohort can be population-based or volunteer-based o Types of be population-be categorized by source population and selection mechanism o More and more cohort studies involve biological specimens, such as blood, urine, toenail, cheek cells, etc. o Multi-center and multi-national collaboration is an effective way to increase sample size. o Current statistical method typically use time-to-event analysis by Cox proportional hazard model.

• 농업과학연구
• /
• 제42권4호
• /
• pp.397-406
• /
• 2015

Quantitative traits are mostly controlled by a large number of genes. Some of these genes tend to have a large effect on quantitative traits in cattle and are known as major genes primarily located at quantitative trait loci (QTL). The genetic merit of animals can be estimated by genomic selection, which uses genome-wide SNP panels and statistical methods that capture the effects of large numbers of SNPs simultaneously. In practice, the accuracy of genomic predictions will depend on the size and structure of reference and training population, the effective population size, the density of marker and the genetic architecture of the traits such as number of loci affecting the traits and distribution of their effects. In this review, we focus on the structure of Hanwoo reference and training population in terms of accuracy of genomic prediction and we then discuss of genetic architecture of intramuscular fat(IMF) and marbling score(MS) to estimate genomic breeding value in real small size of reference population.

• 대한건축학회논문집:구조계
• /
• 제34권12호
• /
• pp.51-56
• /
• 2018

Due to the aging of economically active population in the world, the average age of workers in the domestic construction industry is also steadily increasing. This study analyzes the aging of construction workers in small-size construction sites in Busan, where the aging of the economically active population is the most severe in Korea. As a result of the study on the aging of construction workers in six construction sites with a construction cost of less than 500 million won in Busan, it was found that 65% of the workers were over 50 years of age. In addition, several experts interviews and survey revealed that 'securing welfare facilities for construction workers' and 'diminishing prejudice about the construction industry" were the most urgent and effective methods to overcome the aging problems. The results of this study can be served as basic data to solve the aging problems in the industry.

• Asian-Australasian Journal of Animal Sciences
• /
• 제27권9호
• /
• pp.1368-1372
• /
• 2014

Several studies arduously reported that gayal (Bos frontalis) is an independent bovine species. The population size is shrinking across its distribution. In Bangladesh, it is the only wild relative of domestic cattle and also a less cared animal. Their body size is much bigger than Bangladeshi native cattle and has prominent beef type characters along with the ability to adjust in any adverse environmental conditions. Human interactions and manipulation of biodiversity is affecting the habitats of gayals in recent decades. Besides, the only artificial reproduction center for gayals, Bangladesh Livestock Research Institute (BLRI), has few animals and could not carry out its long term conservation scheme due to a lack of an objective based scientific mission as well as financial support. This indicates that the current population is much more susceptible to stochastic events which might be natural catastrophes, environmental changes or mutations. Further reduction of the population size will sharply reduce genetic diversity. In our recent investigation with 80K indicine single nucleotide polymorphism chip, the $F_{IS}$ (within-population inbreeding) value was reported as $0.061{\pm}0.229$ and the observed ($0.153{\pm}0.139$) and expected ($0.148{\pm}0.143$) heterozygosities indicated a highly inbred and less diverse gayal population in Bangladesh. Prompt action is needed to tape the genetic information of this semi-domesticated bovine species with considerable sample size and try to investigate its potentials together with native zebu cattle for understanding the large phenotypic variations, improvement and conservation of this valuable creature.