Lecture 6 Inbreeding and Crossbreeding
نویسنده
چکیده
Changes in the Mean and Variance Under Inbreeding Inbreeding Inbreeding (mating of related individuals) often results in a change in the mean of a trait compared with its value in a random-mating population. Its importance is that inbreeding is generally harmful and reduces fitness. In particular, inbreeding often causes a reduction of the mean value for quantitative traits associated with reproduction and viability. Inbreeding is intentionally practiced to: • create genetic uniformity of laboratory stocks • produce stocks for crossing (animal and plant breeding)
منابع مشابه
اثر همخونی بر کاهش وزن پشم در برههای لری بختیاری
The aim of this study was to estimate inbreeding coefficient and its impact on wool performance in Lori-Bakhtiari sheep. In this research, wool weight records of 6234 lambs born from 273 rams and 1924 ewes were used. The data were collected at Shahrekord Sholi station during 1990-2010. In total pedigree, 1764 animals were inbred. Averages of inbreeding coefficient for total and inbred populatio...
متن کاملLecture 6
CHANGES IN THE MEAN AND VARIANCE UNDER INBREEDING Inbreeding Inbreeding (mating of related individuals) often results in a change in the mean of a trait compared with its value in a random-mating population. Its importance is that inbreeding is generally harmful and reduces fitness. In particular, inbreeding often causes a reduction of the mean value for quantitative traits associated with repr...
متن کاملThe Genetic Interpretation of Inbreeding Depression and Outbreeding Depression.
Inbreeding with close relatives and outbreeding with members of distant populations can both result in deleterious shifts in the means of fitness-related characters, most likely for very different reasons. Such processes often occur simultaneously and have important implications for the evolution of mating systems, dispersal strategies, and speciation. They are also relevant to the design of br...
متن کاملHigh genetic load in the Pacific oyster Crassostrea gigas.
The causes of inbreeding depression and the converse phenomenon of heterosis or hybrid vigor remain poorly understood despite their scientific and agricultural importance. In bivalve molluscs, related phenomena, marker-associated heterosis and distortion of marker segregation ratios, have been widely reported over the past 25 years. A large load of deleterious recessive mutations could explain ...
متن کاملAccounting for Inbreeding and Crossbreeding in Genetic Evaluation of Large Populations
INTRODUCTION Inbreeding coefficients for 9.3 million registered Holsteins were computed by constructing a small relationship matrix for each animal and its arxestors instead of one large matrix for the whole population. Recent cows averaged 2.0% inbreeding if each pedigree path was extended to the most recent ancestor born before 1960. Inbreeding was underestimated because some pedigrees includ...
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