scholarly journals Minimising inbreeding in small populations by rotational mating with frozen semen

2004 ◽  
Vol 84 (2) ◽  
pp. 87-93 ◽  
Author(s):  
ROSS K. SHEPHERD ◽  
JOHN A. WOOLLIAMS
Keyword(s):  
Gene Pool ◽  
Small Populations ◽  
Asymptotic Level ◽  
Frozen Semen ◽  
Inbreeding Level

Mating plans are investigated in order to minimize inbreeding in small populations when frozen semen is available. For a single dam line it was found that specific sire rotations minimized the asymptotic level of inbreeding when semen is used repeatedly from certain generations. When semen of N foundation (G0) sires is used rotationally over generations it is shown that the inbreeding level asymptotes to 1/(2N+1−2). However, if only G0 sires are used then all genes will eventually descend from the founder sires. Inbreeding can be reduced further by using sires from generation one (G1) and later as this retains genes from the founder dams in the long-term gene pool. If semen from NG0 sires and N unrelated G1 sons is used rotationally then inbreeding asymptotes to (2N−1+1)/(22N+1−2). When there are more founder dams than sires, the asymptotic inbreeding can be reduced even further by using the semen of half-sib G1 sires in rotation. Optimal rotations using full-sib G1 sires or generation 2 (or later) sires will lower the asymptotic inbreeding also, but generally not by much. It was found that when unlimited frozen semen from a specified group of sires was available, the optimal mating plan was achieved by selecting each generation the sire with the least co-ancestry with the current female of the dam line.

Capturing the dynamics of small populations: A retrospective assessment using long‐term data for an island reintroduction

2021 ◽  
Author(s):  
Doug P. Armstrong ◽  
Elizabeth H. Parlato ◽  
Barbara Egli ◽  
Wendy J. Dimond ◽  
Åsa Berggren ◽  
...  
Keyword(s):  
Small Populations ◽  
Retrospective Assessment ◽  
Term Data

scholarly journals Artificial selection and maintenance of genetic variance in the global dairy cow population

2005 ◽  
Vol 360 (1459) ◽  
pp. 1479-1488 ◽  
Author(s):  
S Brotherstone ◽  
M Goddard
Keyword(s):  
Genetic Variation ◽  
Genetic Improvement ◽  
Breeding Value ◽  
Payment Systems ◽  
Frozen Semen ◽  
Best Linear Unbiased ◽  
The Uk ◽  
Selection Algorithms ◽  
Global Population

Genetic improvement of dairy cows, which has increased the milk yield of cows in the UK by 1200 kg per lactation in 12 years, is an excellent example of the application of quantitative genetics to agriculture. The most important traits of dairy cattle are expressed only in females, but the main opportunity for selection is in males. Despite this, genetic improvement was achieved by the invention of a new statistical methodology, called ‘best linear unbiased prediction’ to estimate the breeding value of bulls. Intense selection of the best bulls, combined with the worldwide use of these bulls through artificial insemination and frozen semen, has created a global population and caused concern that the genetic variation available in the future will be reduced. Maintenance of genetic variation and long-term genetic gains would be aided by rational payment systems, use of crossbreeding where profitable, inclusion of all economically important traits in the breeding objective, recognition of genotype by environment interactions and the use of selection algorithms that balance estimated breeding value against the average relationship among the selected animals. Fortunately, all of these things are happening to some degree.

Alemtuzumab Treatment Can Affect CD52 Positive As Well As CD52 Negative GPI-Deficient, Sezary Cells Allowing Long-Term Disease Control

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2491-2491
Author(s):  
C.J.M. Halkes ◽  
I Jedema ◽  
H.M. van Egmond ◽  
L van der Fits ◽  
J.H.F. Falkenburg ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Fold Increase ◽  
Cell Populations ◽  
Proliferative Potential ◽  
Small Populations ◽  
Collateral Damage ◽  
Sézary Cells

Abstract Abstract 2491 Alemtuzumab (ALT) is a monoclonal anti CD52 antibody used for the treatment of CD52 positive lymphoid malignancies and to deplete T cells in vivo and in vitro to prevent graft rejection or GVHD after allogeneic stem cell transplantation (alloSCT). Membrane CD52 expression depends on the presence of a glycosylphosphatidylinositol (GPI) anchor. GPI deficiency is frequently found in small populations of normal and malignant hematopoietic cells, including T and B cells (frequencies from <0.01 to 2%). These cells lack expression of GPI-linked proteins like CD52 as can be detected by absence of staining of FLAER, which is an aerolysin that specifically binds to mammalian GPI anchors. After alloSCT using ALT for T cell depletion, reconstitution of FLAER and CD52 double negative cells is seen, and outgrowth of CD52 negative malignant cell populations has been found after single agent treatment with ALT in malignant diseases. However, GPI deficient cells have been suggested to have a lower proliferative potential and a decreased survival due to their increased susceptibility to spontaneous complement mediated cell lysis, possibly explaining the infrequent dominant outgrowth of GPI deficient clones in healthy individuals. Sézary Syndrome (SS) is an aggressive cutaneous T cell lymphoma characterized by the presence of high numbers of neoplastic T cells expressing CD4 and CD52 in peripheral blood, lymph nodes and skin. Clinical responses in SS patients after single drug treatment with low dosed ALT have been described by several investigators. However, in 6 out of 6 patients analyzed, we found a small population of CD52 and FLAER negative Sézary cells, illustrating that a GPI negative subpopulation is frequently observed which may lead to outgrowth of CD52 negative Sézary cells. We treated 3 patients with successive courses of low dose ALT (10 mg subcutaneously once weekly until circulating malignant cells were < 1,000/mm3) and followed the kinetics of CD52- and CD52+ Sézary cells. Before ALT treatment, a CD4+CD52-FLAER- T cell population was found in all three patients (0.01–0.06% of all circulating CD4+ T cells). As expected, a rapid decrease in absolute numbers of CD4+CD52+FLAER+ cells was observed after ALT treatment (decrease 94 to 100%). Surprisingly, despite the absence of the CD52 target molecule, the absolute number of CD4+CD52-FLAER- T cells also decreased after the first and second treatment cycles in all three patients (decreases between 22 and 96%), indicating that the massive in vivo ALT mediated lysis of CD52+ Sézary cells coincided with collateral damage of CD52- Sézary cells. Between successive treatment courses in the absence of circulating ALT, the absolute numbers of CD4+CD52+FLAER+ T cells showed a more rapid increase compared to CD4+CD52-FLAER- T cells in all patients (median 193 fold increase (range 17–896) versus 9 fold increase (range 2–144) respectively), illustrating a decreased in vivo proliferative potential of these GPI negative cells. After repeated doses of ALT, one of the patients developed resistance to ALT treatment. Phenotype analysis revealed that 97% of the 23,000/mm3 circulating Sézary cells were CD4+CD52-FLAER-. Clonality analysis showed that CD4+CD52+FLAER+ and CD4+CD52-FLAER–Sézary cell populations expressed identical T cell receptor V-beta chains demonstrating that both cell populations are part of the same initial clone of Sézary cells. At present, one year after the start of ALT treatment, reponses are still observed in both other patients without overgrowth of a CD4+CD52-FLAER–Sézary cells. We conclude that despite presence of small populations of CD52 and GPI negative cells in patients with Sézary Syndrome, all patients respond to treatment with alemtuzumab. CD52 negative, GPI deficient Sézary cells showed high susceptibility to collateral damage during antibody treatment. During treatment intervals, CD52+ cells showed a faster recovery compared to CD52- cells, indicating a lower proliferative potential of the GPI deficient Sézary cells. Although, as shown in one patient, ultimate outgrowth of GPI deficient CD52- sezary cells can occur, the capacity to achieve long term control of both CD52+ and CD52- Sézary cells in several patients offers a rationale for treatment of SS with alemtuzumab, possibly in combination with a low dosed cytotoxic drug Disclosures: Off Label Use: Alemtuzumab for treatment of Sezary Syndrome.

scholarly journals The use of frozen semen to minimize inbreeding in small populations

2002 ◽  
Vol 80 (1) ◽  
pp. 27-30 ◽  
Author(s):  
ANNA K. SONESSON ◽  
MIKE E. GODDARD ◽  
THEO H. E. MEUWISSEN
Keyword(s):  
Computer Simulation ◽  
Optimum Design ◽  
Simulation Study ◽  
Genetic Conservation ◽  
Gene Bank ◽  
Small Populations ◽  
Computer Simulation Study ◽  
Simple Scheme ◽  
Alternative Scheme ◽  
Frozen Semen

In this study, we compared the average coancestry and inbreeding levels for two genetic conservation schemes in which frozen semen from a gene bank is used to reduce the inbreeding in a live population. For a simple scheme in which only semen of generation-0 (G0) sires is used, the level of inbreeding asymptotes to 1/(2N), where N is the number of newborn sires in the base generation and rate of inbreeding goes to zero. However, when only sires of G0 are selected, all genes will eventually descend from the founder sires and all genes from the founder dams are lost. We propose an alternative scheme in which N sires from generation 1 (G1), as well as the N sires from G0, have semen conserved, and the semen of G0 and G1 sires is used for dams of odd and even generation numbers, respectively. With this scheme, the level of inbreeding asymptotes to 1/(3N) and the genes of founder dams are also conserved, because 50% of the genes of sires of G1 are derived from the founder dams. A computer simulation study shows that this is the optimum design to minimize inbreeding, even if semen from later generations is available.

CONSERVATION OF ANIMAL GENETIC RESOURCES IN THE USSR

1987 ◽  
Vol 6 ◽  
pp. 15-18
Author(s):  
N.G ‘Dmitriev
Keyword(s):  
Genetic Resources ◽  
Gene Pool ◽  
Genetic Improvement ◽  
Animal Husbandry ◽  
Farm Animals ◽  
Animal Conservation ◽  
Live Animal ◽  
Animal Genetic Resources ◽  
State Plan

SUMMARYMany valuable local breeds of farm animals in the USSR have either been lost or are in an endangered state. Concern about this loss of gene resources has led to the inclusion of a genetic resources programme in the overall state plan for the genetic improvement of livestock. It includes programmes for live animal conservation and setting up of gene banks. The former activity is carried out in special state gene pool farms, one for each geographical zone, where 500 purebred cows are maintained under a rotational outbred system of mating. Semen banks of most local breeds of livestock have also been established at animal husbandry institutes. Current research emphasis is on long term embryo storage and establishment of banks of somatic cells of local breeds.

scholarly journals Evaluation of the cucumber gene pool of the VIR collection on precocity and fruiting period under the conditions of the Lower Volga region

2020 ◽  
pp. 16-21
Author(s):  
T. M. Piskunova ◽  
E. Kh. Sukhanberdina
Keyword(s):  
Gene Pool ◽  
Relative Resistance ◽  
Term Study ◽  
Lower Volga Region ◽  
Long Term Study ◽  
Research Material ◽  
World Collection ◽  
The World ◽  
Early Ripening

Relevance. In connection with the annual epiphytotic development of peronosporosis (Pseudoperonospora cubensis (Berk. and Curt.) Rostow. on cucumber and the absence varieties immune to this disease, it is advisable to create and cultivate precocious varieties and hybrids that can form the main part of the yield before the period of mass spread of the disease. In order to rationally use the cucumber gene pool long-term research of the world collection is carried out to search of sources of yield, precocity and resistance to peronosporosis.Material and methods. The studies were conducted at Volgograd Experimental Station of VIR (Volgograd province). The research material was 370 cucumber accessions from the world collection of VIR. Evaluation of accessions on a complex of signs was carried out according to methodical guidelines of VIR.Results and conclusions. Long-term study of cucumber accessions of various geographical origin showed that the duration of the interphase period "mass seedlings - the first harvest of fruits" did not differ significantly in samples of different geographical groups, most of them belong to the early ripening. It was found that the duration of the fruiting period depended on the degree of resistance of plants to peronosporosis: the higher the resistance of the variety or hybrid, the longer the fruiting period. A number of precocious, yielding hybrids and varieties, as well as samples with a long period of fruiting and relative resistance to peronosporosis, were allocated. The perspective material for the decision of separate problems in breeding of a cucumber is recommended.

Hormonal control of reproduction in cattle

1975 ◽  
Vol 4 ◽  
pp. 71-78 ◽  
Author(s):  
G. E. Lamming ◽  
H. D. Hafs ◽  
J. G. Manns
Keyword(s):  
Dairy Cattle ◽  
Second World War ◽  
Hormonal Control ◽  
Dairy Herds ◽  
High Fertility ◽  
Frozen Semen ◽  
Beef Herds ◽  
Average Size ◽  
Second World

In countries with developed agricultural systems the proportion of dairy cattle inseminated artificially increased substantially following the Second World War, but a similar expansion in the use of artificial insemination (AI) has not been experienced for beef herds. The availability of deep frozen semen provided a further incentive to increase the percentage of dairy cattle artificially inseminated, for the more progressive herd owners soon realized that the technique offered the advantage of a long-term breeding programme with semen from progeny-tested sires available at a relatively modest cost. More recently, however, various developments in herd management have tended to militate against the use of AI in dairy herds, and during the past year there has been a substantial decrease in the total number of dairy cows inseminated which can only be partially explained by the smaller decrease in the size of the national herd. Amongst reasons advanced is the increase in average size of individual herds, resulting in more cows per man and therefore less time available for the observations of oestrus. Since accurate detection of the onset of oestrus is so important in obtaining high fertility following AI, some herd owners have returned to using natural mating. Evidence supporting this view can be derived from the fact that during 1973/74 there was an increase of over one thousand in the number of bull licences issued in England and Wales above the seventeen thousand issued in 1972/73. Of the 18.2 thousand bulls licensed, there were 3.2 thousand crossbred bulls, some obviously for use in dairy herds. The availability of synchronized and controlled ovulation would largely remove the difficulties which have been encountered, and would permit planned management techniques to be more widely applied within such herds.

scholarly journals Pedigree Analysis of Mangalica Pig Breeds

2016 ◽  
Vol 16 (3) ◽  
pp. 701-709 ◽  
Author(s):  
János Posta ◽  
Péter Szabó ◽  
István Komlósi
Keyword(s):  
Genetic Structure ◽  
Genetic Variability ◽  
Gene Pool ◽  
Reference Population ◽  
Pedigree Analysis ◽  
Small Populations ◽  
Gene Conservation ◽  
Generation Interval ◽  
Pig Breeds ◽  
Gene Origin

AbstractAn effective gene conservation programme requires the knowledge of genetic variability of the population. The genetic structure of Mangalica pig breeds (Blonde, Red and Swallow-bellied) was studied from pedigree records. Herdbook data available up to 2011 of registered Mangalica pig breeds (Blonde, Red and Swallow-bellied) were analysed. The number of complete generations was 6 for Blonde and 5 for Red and Swallow-bellied Mangalica whereas the average complete generation equivalent was between 3.51 and 6.01. The average level of inbreeding of the reference population was low (4.07–5.87%). The investigated breeds could be considered as small populations based on the probability of gene origin. The most important ancestor contributed between 9 and 16% of the gene pool of the reference populations. The longest generation interval was found for the sire-to-son pathways whereas the shortest for dam-to-daughter pathways for each breed.

scholarly journals Analysis of external features and live weight of woolly-meaty sheep (ovis aries)

2021 ◽  
Vol 939 (1) ◽  
pp. 012047
Author(s):  
B B Shoyusupov ◽  
N R Ruzibayev ◽  
U R Soatov ◽  
N T Shoymurodov
Keyword(s):  
Body Size ◽  
Gene Pool ◽  
Live Weight ◽  
Ovis Aries ◽  
Frozen Semen ◽  
External Characteristics

Abstract This article addressed the development and the growth of offspring, the external characteristics and the productivity at different breeding periods of woolly-meaty sheep of Uzbekistan. It was observed that wool productivity was higher in sheep rich in wool-meat than ordinary sheep; sheared wool was 1.26 kg (49.6%), after washing it was 0.97 kg (67.8%), wool length was 2.13 (19.2%) higher. Live weights of lambs from ewes in the experimental groups were determined at birth, at 30 days of age, and 3 months of age. From September 1 to September 20 of the year, the live weight, body size and wool productivity of early inseminated ewes were higher than those of inseminated ewes from late October to November 10. The live weight of lambs obtained from artificially inseminated sheep with frozen semen of typical rams in world gene pool considered semi-fine wool in the meat-wool direction was higher than sheep naturally inseminated with pedigree rams. Accordingly, it was heavier by 00.4 kg (9.3%) at the first day of birth, followed by 0.5 kg (6.8%) at 10 days, and 0.4 kg (1.3%) at 3 months of age.

scholarly journals On some possibilities and prospects of gene conservation and utilisation of pig breeds

1999 ◽  
Vol 42 (1) ◽  
pp. 57-66
Author(s):  
M. Wittmann ◽  
J. Dohy
Keyword(s):  
Marker Genes ◽  
Small Populations ◽  
Gene Conservation ◽  
Effective Population ◽  
Pig Breeds ◽  
The World ◽  
Inbreeding Rate ◽  
Closed Populations ◽  
Small Effective Population Size

Abstract. Nowadays, there are 47 rare pig breeds in the world the majority of which in Europe. Disappeared breeds are considered to be 139 breeds (mostly in Europe). The prevention of further losses of needs needs special measurements and methods for maintenance and conservation of genetic values. In spite of a lot of means being available, the conservation programs use the possibilities only moderately. Besides the commonly used testing results, special genetic analysis should be practised and extended widely, including blood groups, enzyme and other protein polymorphisms and the new results of genom analysis (marker genes atc). A proper – and well identified - genetic make up is of minimal precondition for preparing effective mating plans to avoid and reduce Inbreeding rate in closed populations. Besides number of traits and markers, more emphasis should be given to the distribution of the genetic markers on each chromosomes detected. If a chromosome were controlled (detected by at least 5 loci, thre would be round 200 parameters necessary as a minimum for a porper control fo the genomic background of a breed. Whilst it is very diffucult to prevent gene losses in small populations (small effective population size) for long term, reconstruction of them should be comined with cryopreservational and up-to-date DNA-screening.

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