Inbreeding and homozygosity in a closed population of chicken


A New Hampshire line at the research station of the Institute of Animal Sciences was subject of the investigation since 1955.Divided into 15 sublines, the hens (10 to 15 per subline) were mated in a system of rotation in order to avoid inbreeding. The individual inbreeding coefficients were estimated including complete pedigree data about 8100 chickens. For the molecular analysis, DNA was isolated from blood samples of generation 1994 (79 chickens) and plasma samples of generation 1982 (58 chickens). The individuals were typed by 17 markers located in non- coding regions and 6 markers within coding regions. The individual realized inbreeding was determined as the proportion of homozygous loci of all investigated loci.In the investigated New Hampshire line 22 markers were polymorphic showing only few alleles per locus (2 to 4). Comparing the generations of 1982 and 1994, 80% of the loci changed allele frequencies significantly, partly accompanied by losses of alleles in 1994. In 5 loci the observe genotype frequencies deviated significantly from HWE expections in both generations, but in contrast to the theorie mainly with tendency to heterozygosity. Mean degree of homozygosity increased from 56,4% in 1982 to 61,6% in 1994. At the same time the mean estimated coefficient inbreeding (WRIGHT) increased from 18,8% to 24,3%. The low rate of inbreeding was caused by the rotation mating scheme which was used to avoid close inbreeding. The microsatellites were choosen from coding and non-coding regions. In contrast to the majority of 17 markers located in non-coding regions with increasing homozygosity, the 6 microsatellites located within coding regions showed on average an increase of heterozygosity in the New Hampshire line.


Principal Investigators
Seeland, Gerhard Prof. Dr. agr. (Details) (Breeding Methods and Principled Breeding)

Duration of Project
Start date: 11/1998
End date: 05/2000

Research Areas
Genetic markers, genetische Marker, Homocygosity, Homozygotie, Inbreeding, Inzucht

Publications
IRGANG,K.;B.RÖDER;T.HARDGE;S.RISSE u.G.SEELAND (1999): Entwicklung von Inzucht und Homozygotiestatus in einer geschlossenen New-Hampshire-Linie.Vortragstagung der DGfZ/GfT,15./16.09. Gießen. IRGANG,K.;B.RÖDER;T.HARDGE, S.RISSE a. G.SEELAND (1999): Development of estimated and realized inbreeding in a flock of hens over generations; Symp.Poultry Genetics, 06.-08.10., Mariensee. IRGANG,K.;B.RÖDER;T.HARDGE;S:RISSE a.G.SEELAND (2000): Development of inbreeding and homozygosity based on genetic markers in a closed New Hampshire population. XXI World's Poultry Congress, 20.-25.08., Montreal.SEELAND,G.(2001): Inzucht und Verwandtschaft in einer über 4 Jahrzehnte geschlossenen New Hampshire Linie. Festveranst. anl. d. 100. Geburtstages v. Prof. Dr. habil. F. Lützenberg, 09.05.01, HU-Berlin,14-24.IRGANG,K: (2001): Vergleich von Inzucht- und Homozygotieentwicklung anhand molekulargenetischer Marker in einer geschlossenen New Hampshir Linie. Inaugural-Dissertation,HU-Berlin u. FU-Berlin.

Last updated on 2020-10-03 at 16:38