The rate of population inbreeding was 13.14%. Average inbreeding coefficient was 82.13_x10~(-4). The rate of inbreeding in patients with cretinism accounted for 17.35%.

This result indicated that apart fromconsidering the size of animal genetic resources conservation population and ratio offemales and males, the mating system and method of properiy selecting parents shouldbe adopted so as to decrease the rate of inbreeding in practice.

A dynamic selection rule was developed that maximizes the annual genetic response while constraining the rate of inbreeding per year to a predefined value in a population with overlapping generations and different number of age class between sire and dam.

This rule accounts for the animals in population with overlapping population should be divided into sex-age classes,and limits the increase of mean relationship of individuals in parent population, so,the mean rate of inbreeding of new progenies is controlled.

Those highlight the need to maximize the genetic diversity in base population,and to control the rate of inbreeding in selective breeding programs and wild resource protection.

Factors responsible for the elevated rate of inbreeding among the professional/mercantile class and its secular trend are discussed.

The average effective population size was 15.35, which indicated a high rate of inbreeding (5.52%).

Inbreeding and extinction: Effects of rate of inbreeding

However, at the current low populationdensities, the subdivision may markedly furtherincrease the future rate of inbreeding.

Allowing reasonablemutation rates (μ = 10-4), thisimplies a long-term post-glacial effectivepopulation size of Ne ? 350,and a slow average rate of inbreeding ΔF? 0.15% per generation during the c.860 generations (9 500 years) of isolation.

The theoritical results of systems of inbreeding have been discussed in this paper.The general formulae for the heterozygote frequencies.Inbreeding coefficients and the rates of inbreeding for systems of full sib.Alternative parent-offspring and unrestricted Parent-offspring mating involving a single autosomal gene substitution are derived by extrapolation from the change of the heterozygote frequencies of ensuing generations when the population in the initial generation is at equilibrium.These...

The theoritical results of systems of inbreeding have been discussed in this paper.The general formulae for the heterozygote frequencies.Inbreeding coefficients and the rates of inbreeding for systems of full sib.Alternative parent-offspring and unrestricted Parent-offspring mating involving a single autosomal gene substitution are derived by extrapolation from the change of the heterozygote frequencies of ensuing generations when the population in the initial generation is at equilibrium.These formula are different from what are described in the classical memoirs.By the new ones the evaluation of the parameters Ft.Ht and ΔFt given generation t can be made more easily.The limiting values of Ft and Ht for all of three sys- tems of inbreeding have been verified strictly.The exact limiting value of ΔFt for systems of full sib and alternative parent-offspring mating has been found.It is (2/((1+5~(1/2)))~2) and is the core of the rates of inbreeding of all generations.These rates of inbreeding fluctuate by the core up and down alternately and finally approach to it with the range going down each passing generation.

1.规则近交系统的近交系数及杂合体频率的变化规律在经典文献中被归结为一些世代递推公式,以此描述群体的遗传结构。这里,我们通过研究相继世代杂合体频率的变化与平衡的起始群体基因裂频率的联系,为常体的两等位基因位点,导出表达若干近交系统的杂合体频率,近交系数及近交率变化的通式。2.用本文中的公式可以简单地直接计得任一给定世代 t 的近交系数,杂合体频率及近交率,而不象经典公式需要依赖所求参数在以前世代的值。3.严密地求证了全同胞交配系统,交替型及无限型亲子交配系统的近交系数及杂合体频率的极限值。4.求得了全同胞交配系统及交替型亲子交配系统的近交率的准确极限值,它等于(2/(1+5~(1/2))~2)。5.研究了在全同胞交配系统及交替型亲子交配系统中,近交进程的精细变化。发现各世代的近交率以极限值(2/(1+5~(1/2))~2)为中心,左右摇摆,摆幅逐代减小而趋于该值。

In studying the genetic factors of endemic cretinism, we used four approaches. 1. Inbreeding investigation. The rate of population inbreeding was 13.14%. Average inbreeding coefficient was 82.13_x10~(-4). The rate of inbreeding in patients with cretinism accounted for 17.35%. 2. Chromosome analysis. Diploid in 19 healthy subjects was 97.72%. In 74 cretin cases, diploid was found in 93.82%. The karyotype in one of those was 47, XXX. 3. Dermatoglyphic studies in 16 patients with cretinism revealed expansion...

In studying the genetic factors of endemic cretinism, we used four approaches. 1. Inbreeding investigation. The rate of population inbreeding was 13.14%. Average inbreeding coefficient was 82.13_x10~(-4). The rate of inbreeding in patients with cretinism accounted for 17.35%. 2. Chromosome analysis. Diploid in 19 healthy subjects was 97.72%. In 74 cretin cases, diploid was found in 93.82%. The karyotype in one of those was 47, XXX. 3. Dermatoglyphic studies in 16 patients with cretinism revealed expansion of atd angle, abnormal palmar flexion crease and fibular loop or proximal arch of hallucal area was found higher than healthy subjects. As the hallucal arch rises, atd angle expands. 4. Pedigree analysis. The incidence of cousins of patients with cretinism was 3.15%-highest among grandfather-mother-and older brother-younger sister. In cousins of every degree, first degree cousins had the highest incidence. If parents had normal phenotype, their children’s incidence was 86.21%. If one of the parents had cretinism, their children’s incidence was 13.79%. We consider endemic cretinism is a disease with polygenic inheritance. Its heritability is 48%. Although environmental factor has an important role we should not neglect the genetic predisposition in its etiology. The disease may be caused by the combination of these two factors exceeding certain threshold intensity. Thus using“Inheritance-iodine deficiency”to interpret the etiopathogenesis of endemic cretinism is appropriate.

he effect of factorial and nested mating systems on the rates of inbreeding areconsidered for the animal breeding and genetic resounes conservation schemes. In thebreeding selection population, result showed that the new inbreeding for factorialmating system is less than nested mating system. Howevet, in the Fopulations ifcomplete random selecting Parents and restriction on the random selecting parents there are no differences of the new inbreeding for two mating systems.Under themating systems,the new inbreeding...

he effect of factorial and nested mating systems on the rates of inbreeding areconsidered for the animal breeding and genetic resounes conservation schemes. In thebreeding selection population, result showed that the new inbreeding for factorialmating system is less than nested mating system. Howevet, in the Fopulations ifcomplete random selecting Parents and restriction on the random selecting parents there are no differences of the new inbreeding for two mating systems.Under themating systems,the new inbreeding for restriction on the random selecting Parents isless than complete random selecting parents.This result indicated that apart fromconsidering the size of animal genetic resources conservation population and ratio offemales and males, the mating system and method of properiy selecting parents shouldbe adopted so as to decrease the rate of inbreeding in practice.