How calculate? What effects may occur? How to avoid it? and in short how to handle it?
When we talk about kinship, we mean the amount of relationship between two individuals, and how they transmit it to their common ancestry and, above all, even implicitly, of cantidad de genes iguales que pueden tener dos individuos, y recalco pueden tener, pues ahora más que nunca estamos en el terreno de las probabilidades que pueden estar en homozigosis en la descendencia común.
Primero vamos a calcular la cantidad de parentesco, o de consanguinidad que tienen dos individuos con ascendencia común.
Cálculo de consanguinidad
Sabemos que cada individuo recibe la mitad de su carga genética de cada progenitor, o sea, la mitad del padre y la mitad de la madre. Entonces, dos medios hermanos, de padre o madre tienen un 50 por 100 de probabilidades de recibir la misma mitad de la carga genética del progenitor común, lo que es lo mismo, que la probabilidad de tener los mismos genes ambos individuals will, 0.5 x 0.5 = 0.25 (when speaking of odds, as is always done by one, that is, to make it only as a percentage must be multiplied by 100), so obviously have a 25 100 kin, so their son (X) will have a blood relationship of 0.25 x 0.5 = 0.125.
If they are full brothers, father and mother will have to add the other parent, who also is 25 by 100, so the relationship (F) is 50 by 100, or what is the same as the son of both have a kinship of 0.5 x 0.5 = 0.25.
When the common parent is a grandparent, are first cousins, things are a bit more complicated, but not much else, went through 5 individuals, the calculation is therefore 0.55 = 0.5 x 0.5 x 0.5 x 0.5 x 0.5 = 0.03125, therefore the probability of having both individuals the same genes, and transferred to the offspring is of 3.125 for 100, but if you are 2 common grandparents, the probability is 6.25 per 100.
As we can see the kinship between two individuals will never be 100 by 100, unless they are monozygotic twins, formed from the same egg, and therefore have exactly the same DNA.
If we have a gene with 2 alleles, the possibilities for changes in an individual are small, there is a 25 100 chance that is AA, 50 100 chance that is Aa and 25 100, chances of it being aa. Therefore, if we have 2 individuals chosen at random, the probability of having exactly the same combination for this gene should be (1 / 4) = 0.25 (for there to be safe if we 1 / 0, 25 = 4, therefore occur CAD 1 time 4) or 1 instead of every 42 will find two individuals with the same combination in the same allele. If we repeat the operation with another gene, for example we will call gene B, we find the same opportunities, in the same gene, but the probability of having the same combination will now be 0.25 x 0.25 (the probability of A, by probability of B).
AA Aa Aa aa BB AABB AABB AABB
aaBb
AABB Bb Bb AaBb AaBb aaBb
AABB AaBb AaBb aaBb
bb aabb Aabb Aabb Aabb
Inbreeding between two individuals will never be 100 by 100, unless they are monozygotic twins, formed from the same egg, and therefore have exactly the MSIM DNA. Odds
There are combinations that are repeated, but for our calculations we will take the lesser possibility. If we consider that today it is estimated that the number of different genes is a higher mammal is from about 5000, we find that the probability that 2 individuals of the same species with a genome exactly zero is a number followed by 3,011 zeros coma before reaching the first significant figure. Therefore, finding two animals with the same genetic makeup is completely impossible in practice, because obviously the world's population is less than 103 011 dogs (would be written with a 1 followed by 3,011 zeros) number needed to occur at least once this fact.
What we do to make inbreeding is to increase the likelihood that the genomes of inbred animals have genes of the same composition.
In principle, this fact is neither positive nor negative for breeding, but if we take into account the large number of alleles that have been developed over the evolution of races and which are lethal, sublethal or just unwanted, because they cause malformations or defects in the race, and are hidden because they are recessive and consanguinity it does is increase the probability that these alleles are hidden in homozygosity, that is to be expressed in the phenotype, we see principle that inbreeding should not use it discriminately. However, for this reason we can use to detect inbreeding characters or reaffirm our breeding lines, but always very discriminate and carefully.
0 comments:
Post a Comment