As mentioned, the issue with line breeding to the point of inbreeding is that the bad traits are going to compound as much as the good traits are. Learn about inbreeding and how it can hurt a populations genetic diversity. Large effects are documented in wild animal and plant populations, as well as in humans. Inbreeding depression the reduced survival and fertility of offspring of related individuals occurs in wild animal and plant populations as well as in humans, indicating that genetic variation in fitness traits exists in natural populations. The generally observed consequence of inbreeding is a depression effect on various traits. Harvey usserys book suggests some methods for getting around inbreeding problems, but his techniques rely on the infrastructure to keep multiple flocks of chickens separate. Its probably the closest of all the breeding techniques. Kbc is a poultry genetic resource known as song fowl from west. If inbreeding depression is buffered by polyploidization, selffertilization would be favored as a mating system, at least on the first stages of establishment rausch and morgan, 2005. Highthroughput sequencing reveals inbreeding depression. The adobe flash plugin is needed to view this content. Cornell university 2008 mating systems control the movement of genes through time and space, making the evolution of mating systems a. Inbreeding will result in problems within 3 to 4 generations which will cause your line to go extinct unless certain measures are taken. To understand the genetic basis of inbreeding depression and heterosis in rice, maineffect and epistatic qtl associated with inbreeding depression and heterosis for grain yield and biomass in.
Indigenous chicken, heritability, genetic correlation, inbreeding depression, tropical climate. Inbreeding may or may not lead to inbreeding depression, which is a reduction in the fitness in the offspring produced by inbred matings. This phenomenon is well documented in all the major livestock species. Pdf a note on inbreeding effect on productive and reproductive. Inbreeding depression is the decline in performance that is associated with inbreeding.
Published online20may2003 recent approaches into the genetic basis of inbreeding depression in plants david e. If a weakness does arise the breeder can outcross between the different lines to maintain enough variation to avoid inbreeding depression. Ppt inbreeding and inbreeding depression powerpoint presentation free to view id. The objective of this study was to estimate genetic parameters, the rate of inbreeding, and the effect of inbreeding on growth and egg production traits of tc housed in intensive management under a tropical climate. Studies on genetic parameters and inbreeding effects in native chickens are limited, especially for tc. Inbreeding depression in fitness components or fitnessrelated traits is a focus in assessing these costs. Inbreeding effects on flying performance of racing pigeons. Understanding inbreeding depression, purging, and genetic. Selection for reproductive traits in white egg stock using. The relative effects of inbreeding and outbreeding on.
Evaluation of inbreeding in laying hens by applying optimum genetic. Since depression is not necessarily cumulative with continued inbreeding, it is not possible to predict the magnitude of inbreeding depression in any given line. Inbreeding depression was estimated using a linear regression of individual phenotype on inbreeding. So you have no worries that theres going to be chicks that look like igor coming out of eggs from even multiple brother sister pairings.
Estimation of inbreeding rate in a small and limited population of local chickens is very important to prevent inbreeding depression. I believe that you can maintain a strain without breeding this close. Inbreeding depression refers to the decrease or loss of fitness and strength which is mainly caused due to inbreeding. In simpler form, the mating between the relatives in a small population is common and this may lower the populations ability to persist and reproduce which is referred to as inbreeding depression. Know about inbreeding and inbreeding depression, along with the degrees of depression. This study of the relative effects of inbreeding and outbreeding on reproduction in the domestic fowl is based on two years observations of triallel matings of hens having an inbred, outbred, and crossbred origin. Recent approaches into the genetic basis of inbreeding.
You must avoid the practice of inbreeding because it brings out many of the. Inbreeding is not that much of a problem with chickens. Inbreeding depression an overview sciencedirect topics. Generally, inbreeding has very little effect on bw of lhkk chicken. Deleterious mutations probably play a major role in causing inbreeding depression. Heterosis and inbreeding depression in f2 populations of.
A loss of vigor and general health that sometimes characterizes organisms that are the product of inbreeding. In turkeys inbreeding effects on hatchability were more pronounced than in chickens, with substantial maternal effects. A comparison of pedigree and dnabased measures for. Inbreeding depression is also related to high heterosis in f 1 hybrids and has to search for moderate type of heterosis which has some stability to have less inbreeding depression at f 2 level 3.
Can inbreeding have negative effects, cause diseases or disabilities. Inbreeding in small populations of fowl undergoing selection. When it finally does appear, the signs may be subtle. Whenever this becomes a problem, selected animals of the breeding population should be mated figure 9. Number of eggs laid and egg weight were recorded for each hen individually for a 5day week.
Inbreeding depression is often the result of a population bottleneck. It is possible to breed a couple inbred lines then cross those lines for vigor. Polyploidy, inbreeding depression, and the evolution of mating systems in flowering plants brian c. Among the many relations established by these observations and reported in the following pages, the data with respect to inbreeding and outbreeding show that.
Inbreeding depression was estimated using a linear regression of individual phenotype on inbreeding coefficient. Chicken genome plucked bare by inbreeding new scientist. Highthroughput sequencing reveals inbreeding depression in a natural population joseph i. Can i breed multiple generations with one rooster only. This 18 different blood is often enough to keep the line from running into inbreeding depression. Aaron, animal and food sciences inbreeding is broadly defined as the mating of individuals that are related. Inbreeding depression, purging and genetic rescue are recognized as elements to be considered in conservation programs, and genomic monitoring of.
Since inbreeding depression and heterosis from crossbreeding are essentially opposite effects, it is not surprising that the same traits that respond well to crossbreeding will respond adversely to inbreeding. A comparison of pedigree and dnabased measures for identifying inbreeding depression in the critically endangered attwaters prairie chicken susan c. Inbreeding depression has the greatest effect on reproductive traits, followed by growth traits, with little or no effect on carcass traits. Do a search on inbreeding to find the other topic strings discussing why. Genetic parameters and inbreeding effects for production traits of thai native chickens. Results for inbreeding depression were negligible for egg production traits e. Inbreeding in birds is nothing like inbreeding in mammals. In both populations the deepest inbreeding depression was observed for pef. Prairie chickens in illinois were nearly extinct by 1994. Hoffman a,1, fraser simpson b, patrice david c, jolianne m. Strictly speaking, however, all animals within a breed are related.
Estimation of inbreeding rate in kokok balenggek chicken. In most cases, it is going to take half a dozen generations at least for you to see any signs of inbreeding in your flock. Overdominant epistatic loci are the primary genetic basis. Allelic and nonallelic interactions of genes in presence of specific environmental effects will lead us to successful heterosis results. Ppt inbreeding and inbreeding depression powerpoint. Inbreeding depression is the loss of viability or function resulting from excess inbreeding, as noted in many populations including plant, dog and human where the negative consequences of inbreeding have been most commonly noted. Inbreeding and inbreeding depression on reproduction and. To gain insight into inbreed ing depression in potato, we evaluated the mutation burden in 151 diploid potatoes and obtained 344,831 predicted deleterious substitutions. Influence of inbreeding on egg production in the domestic fowl1. You might notice physical defects when your chickens hatch, such as missing eyes or twisted beaks. Population biological fitness refers to an organisms ability to survive and perpetuate its genetic material.
The thai native chicken tc is the most popular local breed among rural farmers. Preventing inbreeding in a small chicken flock avian. Intercrossing inbred strains improves yield heterosis. Inbreeding depression was not observed for any trait, indicating that selection compensated for any negative effects of inbreeding. Breeding pure breeds of chickens tim daniels last updated. Agricultural industry biological sciences body weight egg industry international economic relations.
Inbreeding and inbreeding depression on reproduction and production traits of white leghorn lines selected for egg production traits. Duck and chicken inbreeding welcome to the homesteading. Inbreeding and inbreeding depression in endangered red. Pdf inbreeding effect on performance of rhode island chickens. Genetic parameters and inbreeding effects for production traits of. Inbreeding and inbreeding depression inbreeding is mating among relatives which increases homozygosity why is inbreeding a conservation concern. Inbreeding depression is the reduced survival and fertility of offspring of related individuals. Inbreeding depression inbreeding depression ibd is the effect of inbreeding measured as the reduction in mean phenotypic performance with increasing levels of inbreeding within a population falconer and mackay, 1996. Pdf inbreeding depression and its evolutionary consequences. If so, is there any rule of thumb after how many generations i should get some foreign chickens or maybe just a rooster. Genetic parameters and inbreeding effects for production. However, inbreeding had a low negative effect on bw1d p inbreeding depression is the reduced biological fitness in a given population as a result of inbreeding, or breeding of related individuals. Even more pronounced inbreeding effects were observed for japanese quail and partridges, with inbreeding depression of almost 30 percent for embryo viability and 14 percent for maternal inbreeding.
1038 265 1513 819 505 613 394 1287 402 1004 962 720 110 1066 1564 833 751 416 1139 921 1250 857 1415 191 1167 829 2 510 334 1490 461 1209