• 한국양식학회지
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• 제19권2호
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• pp.99-108
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• 2006

Sex of the Nile tilapia Oreochromis niloticus is mainly determined by an XX/XY system. However, accumulating evidences suggest the existence of additional sex modifying factors including environmental, autosomal and parental influences. In order to investigate the possibility of parental effects on sex ratios of tilapia progenies, in this study, a series of crosses was carried out using gynogenetic clonal fish, neomales, normal males and females, and YY fish. Crosses between clonal XX male and clonal female have yielded only female progenies and no parental influences were observed. However, in the crosses between clonal males and normal females, female parents were significantly associated with the progeny sex ratios ($X^2$=20.046, 7 d.f., p<0.01). Progeny sex ratios from the crosses between neomales and normal females ($X^2$=60.491, 5 d.f and $X^2$=28.072, 2 d.f.) also showed significant association with female parents (P<0.001). The stability of progeny sex ratios from repeated spawns were confirmed by using 6 different parental pairs. In 16 crosses between normal males and normal females, sex ratios of progenies showed clear maternal influences, and further analysis of the results revealed a negative correlation ($r^2$=0.7718, p<0.05) between the sex ratios of progenies from two different males, indicating a strong paternal influence. No statistically significant relationship between survival rates and sex ratios of progenies was observed in any genotypic groups. Taken together, the influence of parental pairs on progeny sex ratios in this species is evident although the cause of this influence is not clear.

• 한국동물학회지
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• 제13권1호
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• pp.15-20
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• 1970

초파리의 성 염색체의 구성 여하에 따라 그 제 3염색체의 분리가 달라지는가를 조사하기 위하여 성 염색체의 구성이 다른 8가지 인자형을 만들고 제 3염색체 marker로서 e와 se를 이용하여 se의 분리를 k값으로 검토하고 아울러 성비를 조사 검토한 결과는 다음과 같다. 1. se의 분리 즉 k 값은 인자형간에 그리고 성간에 매우 유의적인 차를 보였으며 인자형과 성과의 상호작용도 유의적 차이를 보여 주었다. 이것은 분명히 se 제3염색체의 분리가 성 염색체의 구서에 영향을 받은 것을 말해 준다. 2. k(여) 값이나 k(남)값은 다 같이 인자형간에 유의적 차이를 볼 수 없다. 3. se자손의 성비는 인자형간에 매우 유의적 차이를 보였으나 e자손에서는 뚜렷한 차이를 볼수 없었다. 4. 평균적으로 k(남) 값은 k(여)값보다 높고, se자손의 성비는 e자손의 성비보다 높았다. 5. 이러한 결과는 어떤 종류의 prezygotic selection이 작용하는 것으로 해석할수 있는데, 즉 e 제3염색체와 Y염색체의 조합이 수정전에 감수되는 것으로 생각할 수 있다. 이러한 문제는 종래 초파리 등에서 실시했던 생존력 추정을 재 평가할 필요성을 말해주는 것이다.

• 한국양식학회지
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• 제20권3호
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• pp.190-193
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• 2007

대농갱이, Leiocassis ussuriensis의 유도된 자성발생성 이배체의 초기 생존율, 초기 성장 및 성비를 분석하였다. 대농갱이 자성발생성 이배체는 일반 대농갱이 이배체 대조군과 비교 시 부화 180일까지 생존 및 성장 형질에서 모두 차이를 나타내지 않았다(P>0.05). 자성발생성 이배체는 부화 10주째 암수 판별이 용이한 수준의 난모세포 발달 정도를 보였고 일반 대농갱이 암컷과 난소 발달에 있어 유사하였다. 부화 10주째 생식소 조직학적 분석 결과 일반 대농갱이 이배체 자손들은 1:1의 암수 비율을 나타낸 반면, 자성발생성 이배체 자손들은 모두 암컷으로 판별됨으로써 본 어종의 성 결정 기구는 XX-XY를 기본으로 하는 암컷 동형접합형인 것으로 나타났다.

• 한국양식학회지
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• 제9권2호
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• pp.125-132
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• 1996

본 연구는 성전환된 자성발생성 2배체 수컷의 정액을 보통 암컷 및 자성발생성 2배체 암컷의 성숙란에 인공수정시킨 후 자손의 성비를 분석하였다. 자성발생성 수컷의 유도는 자성발생성 2배체를 전장 13.5 mm에서 57.6 mm까지 62일간 $17{\alpha}$-methyltestosterone 10 ppb의 농도로 침지 처리하여 유도하였다. 자손 검정 결과, 보통 암컷과 자성발생성 수컷 교배군의 암컷 유도율은 평균 $37.4\%$로 낮게 나타났다. 그러나 자성발생성 2배체 암컷과 자성발생성 수컷 교배군에서는 8개 실험군 중 6개 실험군에서 $100\%$ 암컷이 유도 되었고 2개 실험군에서는 $96.9\%$ 및 $95\%$ 암컷이 유도되어, 전체 $99\%$ 의 암컷 유도율을 나타내었다. 이러한 결과는 자성발생성 2배체 암컷과 성전환된 자성발생성 2배체 수컷이 정상적인 생식 기능을 통해 교배되어 전 암컷 집단을 생산할 수 있음을 시사한다.

• 한국응용곤충학회:학술대회논문집
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• 한국응용곤충학회 2000년도 합동 춘계 학술발표회
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• pp.128-128
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• 2000

• International Journal of Industrial Entomology and Biomaterials
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• 제29권1호
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• pp.128-134
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• 2014

Nesolynx thymus Girault (Hymenoptera: Eulophidae) is one among 20 hymenopteran parasitoids reported to attack the uzi fly, Exorista bombycis, which in turn infests the silkworm, Bombyx mori accounting a cocoon yield loss of 10-20%. A host of factors viz., age and size of host, age and size of parasitoid, availability of host, temperature and quality of host are reported to influence the reproductive efficiency of the parasitoids. In the present study an attempt was made to record the influence of foraging parasitoid density on their reproductive performance. Three day-old uzi pupae were offered to varying numbers (1 - 10) of 2 day old Nesolynx thymus adults for parasitization. The progeny production per pupa (84.44 - 132.77) increased significantly with increase in the number of foraging parasitoid adults (1 - 10) however, progeny production per female decreased. The sex ratio (M : F) (1:25.49 - 1:1.53) decreased significantly with increase in foraging parasitoid adults. The morphometric parameters except female abdomen width of first generation parasitoid showed significant negative correlation with number of foraging adults. However, correlation between the parasitoid size in first generation and their reproductive performance was nonsignificant.

• 한국수정란이식학회지
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• 제31권1호
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• pp.65-72
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• 2016

This study was conducted to examine effects of mating type on the growth traits in an $F_2$ population produced by reciprocal intercrosses between Landrace and the Jeju Native Black pig (JBP). The $F_2$ progeny were produced by two different mating types based on the grand dams of founder breeds JBP (Cross_1) and Landrace (Cross_2). The body weights at 21 days after birth (BW21D) was significantly different between Cross_1 and Cross_2 (P<0.05), showing that the BW21D of Cross_1 has about 0.25 kg heavier than Cross_2. The significant differences were found between males and females for the growth traits including the body weights (BWB, BW21D, BW70D and BW140D) and average daily gains (ADG, eADG and lADG) (P<0.05). Males were heavier BWB, BW21D and BW140D levels, and higher ADG and lADG levels than females. On the other hand, females had heavier BW70D and higher eADG levels than those of males. When considering the mating types and sex simultaneously the Cross_2 males had the heaviest BW140D among the combinations of cross and sex. In conclusion, it is desirable to choose Landrace as grand dams in the reciprocal intercrosses between Landrace and JBP for producing their progeny construction and to plan the production of $F_2$ males for industrial purposes. These results suggested that it may be one of useful strategies to improve the productivity through out selection of the mating type of founder breeds and the progeny sex, especially in Landrace, JBP and their related populations.

• Asian-Australasian Journal of Animal Sciences
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• 제26권10호
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• pp.1379-1387
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• 2013

In a majority of mammals, male infants have heavier body mass and grow faster than female infants. Accordingly, male offspring nursing requires a much greater maternal energy contribution to lactation. It is possible that the maternal-fetal immunoendocrine dialog plays an important role in female preparation for lactation during pregnancy. Immune system genes are an integral part of gene regulatory networks in lactation and tumor necrosis factor alpha ($TNF{\alpha}$) is a proinflammatory cytokine that also plays an important role in normal mammary gland development. The aim of this study was to evaluate the influence of the sex of calf and/or the -824A/G polymorphism in the promoter region of $TNF{\alpha}$ gene on milk performance traits in Black Pied cattle over the course of lactation. We also studied the allele frequency differences of -824A/G variants across several cattle breeds, which were bred in different climatic conditions. The G allele frequency decreased gradually over the course of lactation events in the Black Pied dairy cattle because of a higher culling rate of cows with the G/G genotype (p<0.001). In contrast to the genotypes A/A and A/G, cows with G/G genotype showed significant variability of milk and milk fat yield subject to sex of delivered calf. Milk yield and milk fat yield were significantly higher in the case of birth of a bull calf than with a heifer calf (p<0.03). The G allele frequency varies from 48% to 58% in Grey Ukrainian and Black Pied cattle to 77% in aboriginal Yakut cattle. Our results suggest that the $TNF{\alpha}$-824A/G gene polymorphism may have an influence on the reproductive efforts of cows over the course of lactation events depending on the sex of progeny. Allocation of resources according to sex of the calf allows optimizing the energy cost of lactation. This may be a probable reason for high G allele frequency in Yakut cattle breeding in extreme environmental conditions. Similarly, the dramatic fall in milk production after birth of a heifer calf increases the probability of culling for the cows with the G/G genotype in animal husbandry.

• 한국가축번식학회지
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• 제13권1호
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• pp.40-48
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• 1989

Guppy fry were treated for the first 40 days of life with 0, 20, 40, 60 & 100$\mu\textrm{g}$ of estradiol per gram of food in order to change the sex of normal males to functional females(genetic male). The present investigation deals with the effects of steroid hormones, such as $\beta$-estradiol and testosterone, on the sex differentiation in guppy and tilapia. The results obtained were summarized as follows. 1. In B (20$\mu\textrm{g}$/g diet) group 17$\beta$-estradiol-treated, 67.8% of male offsprings were produced. 2. In D (60$\mu\textrm{g}$/g diet) group 17$\beta$-treated, 67% of female offsprings were produced. 3. B, D groups of genetic male brooders had significantly different effects (P<0.01) upon sex ratios of their progeny. 4. This strongly indicates that sex direction has been achieved and that the male is the heterogametic sex. 5. The group that produced the highest percentage of male offspring(male percentage of observed number to expected number was 91%) contained only full-sibling male brooders to the sex-reversed female brooders. 6. After 7 months following treatment, the sex-reversed males had ovarian portion in the anterior region and a testicular portion in the posterior region of the same intersexual gonad, respectively. 7. At 7 months after treatment, the ovareis revealed a complete arrest of the ovarian formation, and appearances of spermatogenetic cell cysts among surviving auxocytes. 8. In most of sex-reversed fish, anterior portion of test is was devoid of sperm ducts including the seminal vesicle and vas deferens. 9. The male transferrin showed two strong bands, while the female transferrin showed a single weak band. 10. One of the two bands of male transferrin showed the same mobility with band of female transferrin.

• International Journal of Industrial Entomology and Biomaterials
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• 제4권2호
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• pp.117-120
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• 2002

Scelionid eggParasitoids Play an important role in biological control of some economically important pentatomids. Stink bug (Canthecona furcellatta Wolff,) is an important predator of Tasar silkworm larvae (Antheraea mylitta D.) and causes 30-40 percent loss in tasar silk industry. Psix striaticeps (Scelionid: Hymenoptera) has been found to be an important egg parasitoid. The parasitization potential of f striaticeps is mere than 60 percent and the sex ratio is female oriented. Studies indicate that the maintenance of existing scelionid population by avoiding harmful practices and the augmentation of scelionids either directly releasing them in the field or by indirectly making the field environment more favorable for them is an important aspect to control the pentatomid population in sericulture. Female bias sex ratio is advantageous to increase the parasitoid population in the field. 24-hour-old egg of stink bug and one-day old parasitoid is suitable for producing maximum progeny. 1 : 30 of parasitoid: host ratio is needed to regulate the estimated population in silkworm rearing field.