• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• 제2권2호
• /
• pp.108-113
• /
• 2021

Detrimental effects of inbreeding have been studied by many researchers for a long time. However, only a few studies have shown the occurrence of inbreeding depression due to evolutionary changes as a purging process. In this study, two different populations (inbreeding and outbreeding) of Drosophila melanogaster were compared to assess inbreeding effects on artificial population bottlenecks. For inbreeding conditions, a couple of D. melanogaster (one virgin and one male) were selected from an inbred population and cultured in a vial. For outbreeding conditions, a couple of D. melanogaster were selected from different populations and cultured in a vial. There were significant differences in body lengths of adults, but not in other parameters such as the total number of adults, the rate of survival, and the rate of wing mutants. The mean body length of adults of outbreeding populations was longer than that of inbreeding populations in the first generation (G1; P = 0.004), but not in the second generation (G2; P = 0.066). Although the other three parameters (total number of adults, rate of survival, and rate of wing mutants) showed differences in their mean values between inbreeding and outbreeding populations, these differences were not statistically significant. This might be due to genetic purging. This study demonstrated one additional experimental case related to inbreeding depression in artificial bottlenecked populations. Further studies are necessary to confirm the clear interaction between inbreeding depression and genetic purging using more generations and replicates (or samples) of D. melanogaster.

• Journal of Plant Biology
• /
• 제39권3호
• /
• pp.203-207
• /
• 1996

On the basis of karyotypic analysis performed by conventional staining and Giemas C-banding technique, cytological relationship was inferred for 21 lines of Paeonia lactiflora Pal. cultivated in Korea. It was very difficult to infer their organized karyotypic classification system using the composition of somatic chromosomes involving sat-chromosomes, relative length of chromosomes, arm ratio and karyotypic formulae by conventional staining. From the distribution and number of Giemsa C-bands on the chromosomes b and c, 21 lines can be subclassified into 5 groups. It seems that the karyotypic polymorphism is observed in 21 lines of cultivated P. lactiflora because peony mainly propagates by outbreeding.

• Journal of Ecology and Environment
• /
• 제30권4호
• /
• pp.315-318
• /
• 2007

Cooperative or non-territorial permanently social spiders are believed to have evolved from species showing subsocial maternal care. The transition from subsocial to cooperative social groups probably involved a transition from an outbreeding breeding system to one with inbreeding. Nepotistic recognition among siblings should facilitate the evolution of social cooperation through avoidance of inbreeding and maintenance of mutual tolerance between siblings. We conducted experiments to determine whether a mechanism for sibling recognition is present in the subsocial spider, Coelotes terrestris which displays extended maternal care in the form of food provisioning. The numbers of surviving individuals within unfed groups were observed and compared between non-sibling groups of ten spiderlings and groups of ten siblings. The number of survivors differed significantly between groups, with consistently fewer spiderlings surviving in the non-sibling groups than the sibling groups over the study period. This result suggests that sibling recognition and nepotism do occur in this subsocial species. The nepotism involved in the maternal social organization of the Coelotes might be an example of a preadaptation facilitating the evolution of permanent social life.

• International Journal of Industrial Entomology and Biomaterials
• /
• 제10권2호
• /
• pp.95-99
• /
• 2005

A breeding plan was carried out on four commercial strains of silkworm (Bombyx mori L.) 101, 102, 103 and 104 to improve some important traits. Genetic gain or response to selection $({\Delta}G)$, heritability of cocoon shell weight (CSW) and specific combining ability effects were estimated to determine the strains that can be improved. Strain 101 had lowest heritabitity, ${\Delta}G$ and viability. Strain 102 was acceptable in selection response but its viability was low. Therefore these two strains were not suitable for more selection. As a result, only lines 103 and 104 were chosen for further improvement. Intra population selection based on independent culling level method practiced from third to sixth generation for both productive and viability traits simultaneously. While CSW and CW had increasingly enhanced during primary generations, they went slightly up after third generation. According to negative genetic correlation, viability decreased during primary generations, but after third generation that paid attention to balanced development of both productive and viability traits, viability increased so that the pupation rate reached to $91\%$ in 103 and $97\%$ in 104 for last generation $(G_8)$.

• 한국패류학회지
• /
• 제30권4호
• /
• pp.415-419
• /
• 2014

북방전복의 근친교배로 인한 근교약세현상의 유무를 명확히 하기 위하여 근친교배 2가계 (AA 및 BB)와 비근친교배 (ww1 및 ww2) 2가계를 같은날 동시에 생산하여 유생단계부터 동일한 수조에 혼합 사육관리한 후 친자확인 기술을 통하여 4개월째 및 10개월째 각각의 가계별 생존율 및 성장을 비교분석하였다. 성장의 경우, 4개월째 근친교배구 AA가계만이 비근친교배구 ww1 및 ww2가계보다 유의적으로 낮은 값으로 나타났지만, 10개월째는 근친교배구 AA가계 및 BB가계 모두 비근친교배구 ww1 및 ww2가계보다 유의적으로 낮은 값을 나타냈다. 또한 생존율에 있어서도 근친교배구가 비근친교배구에 비하여 낮은 값을 나타내었다. 이것은 한세대의 근친교배(근교계수 : 0.25) 에 있어서도 근교약세현상이 나타난다는 것을 보고하고 있다.

• Animal cells and systems
• /
• 제8권4호
• /
• pp.289-294
• /
• 2004

Bupleurum latissimum is a narrowly endemic and endangered plant, restricted to only two small populations on steep cliffs of a small island, Ulleung Island, in Korea. The genetic diversity and population differentiation in the two remnant populations of the species were investigated using RAPD (random amplified polymorphic DNA) analysis. The Neis gene diversities were 0.146 in the smaller population of 45 individuals, and 0.151 in the larger population of 61 individuals. The genetic variation was not significantly different between these two populations. Genetic diversity within populations was not low considering the very small size of populations. Analysis of molecular variance (AMOVA) revealed higher variation within populations (65.9%) than genetic differentiation between them (34.1%). B. latissimum revealed higher population differentiation than other outbreeding species. The differentiation of the populations corresponded to low gene flow (Nem = 0.482). The cluster and principal coordination analyses provide strong support for high population differentiation, showing that all individuals of the two populations have built up population-specific clusters. Although gene flow between the two populations of B. latissimum was limited, they have preserved relatively high levels of genetic variation.

• 한국가축번식학회지
• /
• 제27권2호
• /
• pp.179-185
• /
• 2003

본 연구는 생체 내 세포 및 조직배양기로서의 면역결핍동물을 개발할 목적으로 proximal Ick promoter와 DT-A유전자를 이용하여 형질전환생쥐를 생산하였고 형질전환생쥐의 면역기관에서 Di-phteria toxin이 발현되어 T-cell이 결핍되는지를 분석하였다. 총 암수 2마리의 형질전환생쥐를 PCR과 South-ern blotting으로 분석하여 얻었으며 이식유전자의 copy수는 약 2∼3 copy가 정착된 것으로 확인되었다. 형질전환생쥐의 thymus, spleen, liver 조직을 분리한 후 total RNA를 추출하여 poly(dT) primer 와 DT 특이적 primer를 이용하여 RT-PCR수행 결과 형질전환생쥐의 thymus, spleen, liver에서 DT gene이 발현되고 있는 것을 확인할 수 있었다. 형질전환생쥐의 이들 조직간에 DT 발현량에는 큰차이는 없는 것으로 확인되었다. 형질전환생쥐의 혈액에서 적혈구, 백혈구 ,혈소판, 헤모글로빈 등이 정상생쥐보다 감소되었고 특히 백혈구수와 혈소판의 수가 크게 감소되어 있는 것으로 나타났다. 또한 형질전환생쥐의 혈액을 CD3 antibody를 이용하여 FACS 분석을 실시하여 형질전환생쥐의 혈액 중 T-cell이 수가 비정상적으로 줄어든 것을 확인할 수 있었다. 본 연구에서는 Ick-DT 형질전환생쥐에서 DT유전자의 발현에 의한 T-cell 결핍을 유도할 수 있는 것으로 나타나 이를 바탕으로 돼지를 이용한 사람의 이종장기 배양용 형질전환동물을 생산하여 응용될 수 있을 것으로 사료된다.