it is a brief presentation about nucleus breeding system, their types, assisted reproductive techniques etc.

1. effect of inbreeding and out breeding on population structure
Speaker:
Garima Choudhary
Teaching associate, LRS,
Kodemdesar
Seminar on
Department of Animal Genetics
and Breeding
N
M
C

2. overview
1. introduction
2. effect of inbreeding on
population structure
3. Ways to minimize inbreeding
4. effect of out breeding on
population structure
5. conclusion

3. introduction
 Inbreeding: mating of closely related to each other than the average relationship
between all individuals of the population
 Out breeding: mating of unrelated individuals

4.  1.Effect of inbreeding on population mean-inbreeding depression
 2.Effect of inbreeding on variance
 3.wright equilibrium- zygote proportion under inbreeding

5. 1.Effect of inbreeding on population mean-
inbreeding depression
 Reduction in the mean phenotypic value shown characters connected with
reproductive capaciy , vigiour, physiological efficiency, fertility, litter size in pig,
reduction in milk yield due to repeated inbreeding

6.  Cont..
 MF = p2a+pqaF+2pqd-2pqdF-q2a-pqaF
 = a(p-q)+2pqd-2pqdF
 = Mo-2pqdF
 Mo= mean value of a charatcer before inbreeding
 Mf= mean value of the popuation for a partcular character after inbreeing
 F= inbreeding coefficient of the individual
 D= degree of dominance
 P= frequency of one allele
 Q= frequency of another allele
Genotype Frequency value Frequency*val
ue
A1A1 P2+pqF +a P2a+pqaF
A1A2 2pq-2pqF d 2pqd-2pqdF
A2A2 q2+pqF -a -q2a-pqaF

7.  Total genetic variance in whole popuation after inbreeding
 V= VGw+VGb
 =Vg (1-F)+2FVG
 =VG(1+F)

8. Wright equilibrium-zygote proportion under
inbreeding
genotype A1A1 A1A2 A2A2
Frequency P2+pqF 2pq(1-F) Q2+pqF
D H R
Where D+H+R=1, these genotypic frequency remain
constant with constant value of F from generation to
generation is called wright equilibrium.

9. Other genetic effects of inbreeding
 increases homozygosity without affecting the gene
frequency.
 Decrease overdominance by changing Aa genotype
to AA and aa
 Fixes character in an inbred popuation

10. Phenotypic effects of inbreeding
 adverse effect particularly on fitness traits like
reproduction vigor and growth trait.
 depress the growth rate in the farm animals .
 The reproductive efficiency is reduce with inbreeding in
farm animals.
 increase in death rate and hence loss in vigor. increase
prepotency
 genetic defects which are mostly recessive in inheritance
and remain hidden in out breed animals.

11. Genetic effect of outbreeding
increase heterozygosity
Important and peculiar characteristic of outbreeding is
that the maximum heterozygosity is attained in first
generation outcrosses and goes on decreasing
subsequent generation by random mating of outbred.
( due to segregation of genes)
The outbred cannot breed true because of
heterozygosity and hence the selection is less effective
among outbred.

12. Change of mean on outbreeding-heterosis
 Heterosis- superiority of outbreds/crossbred over the
average of their parents
 By G.H. shull (1912)
 Types- negative, positive, parental, individual
 Heterosis in F1= mean of F1 offspring-mean of parent
breed
 %Heterosis= mean of F1 progeny-mean of parent
breed/mean of parent breed *100

13. Heterosis between two population
 HF1= dy2
 HF1= heterosis in F1
 D= dominance
 Y2= square of differnce in gene frequencies for a particular locus
 HF2= ½ HF1

14. Conclusion
 Traits which are governed by additive gene action neither show inbreeding
depression nor heterosis
 Depend upon directional dominance
 Loci without dominance d=0 cause neither hetrosis nor inbreeding depression
 Non additive gene action is responsible for inbreeding depression and hetrosis.