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Kirsty5278
Platinum Member
 England
2682 Posts |
 Posted - 19 Dec 2007 : 9:05:55 PM
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Have just subscribed to all pedigree database and I am now totally confused....
could anyone explain line breeding and what all those numbers mean please!!
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Kirsty5278
Platinum Member
England
2682 Posts |
Posted - 19 Dec 2007 : 9:07:40 PM
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8 Generation Coefficient of Inbreeding: 4.07114028930664% - what does that mean??
I'm very ignorant on the subject of bloodlines etc and I am trying to educate myself!! |
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georgiauk
Platinum Member
United Kingdom
2605 Posts |
Posted - 19 Dec 2007 : 10:44:35 PM
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This is probably going to be a very bad explanation but here goes......
Inbreeding Stats: eg; 7s 6d 4s 3s 5d etc. this tells you where in the pedigree they are and which side
7s = 7th generation on the sire side, 6d = 6th generation on the dams side etc etc.
Crosses: my understanding is this is how many times a particular horses appears in the pedigree.
Lines: Red figure is the dams side, blue is the sire and this indicates which side of the pedigree that particular horse appears and how many times.
Blood %: Tells you how much of the ancestors blood your horse carries.
Hope this helps and appologies if it isn't correct |
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pat ww
Platinum Member
United Kingdom
3459 Posts |
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Kirsty5278
Platinum Member
England
2682 Posts |
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Athena
Silver Member
England
442 Posts |
Posted - 21 Dec 2007 : 9:07:25 PM
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Checkout www.nbii.gov/portal/server.pt?open=512&objID=403&&PageID=574&mode=2&in_hi_userid=2&cached=true
Sample of text below:
Inbreeding and Relatedness
Small effective population size can result in a high occurrence of inbreeding, or mating between close relatives. One of the effects of inbreeding is a decrease in the heterozygosity (increase in homozygosity) of the population as a whole, which means a decrease in the number of heterozygous genes in the individuals. This effect places individuals and the population at a greater risk from homozygous recessive diseases that result from inheriting a copy of the same recessive allele from both parents. The impact of accumulating deleterious homozygous traits is called inbreeding depression - the loss in population vigor due to loss in genetic variability or genetic options.
In the 1950's, Sewell Wright developed a set of parameters called F statistics. The simplest of these is the inbreeding coefficient defined as the probability that two homologous (same) alleles present in the same individual are identical by descent. The inbreeding coefficient (F) is calculated by comparing the expected heterozygosity with observed heterozygosity ( ), and ranges from -1 (no inbreeding) to +1 (complete identity).
If the values for both observed and expected heterozygosity are the same, F will be zero. A positive value indicates that there is an increased number of homozygotes, and population may be inbred - the larger the number, the greater the extent of inbreeding. A negative value indicates that there are more heterozygous individuals than would be expected; this might happen for the first few generations after two previously isolated populations become one.
In the example above: = 10 and = 24.368 for the heterozygote, thus
F = (10 - 24.368) / 10 = -1.43
We determined earlier (using ) that the difference between the observed and expected is not likely due to chance. However, since there is an increase in the expected number of heterozygotes, inbreeding can be ruled out as a possible population dynamic that is influencing the genotype frequencies.
This is technical but worth the trouble of going through. Try www.tenset.co.uk/fspeed/fspeed.html for a free download that allows you to calculate Wright's coefficient of inbreeding for any pedigree animal - providing you have the pedigree info to input.
Have fun. Alexia
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