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العنوان
Elucidation and Examination of Molecular Genetic Markers Association with Goats Twinning Ability /
المؤلف
Abd El-Halim, Heba Abd El-Halim Mohammed.
هيئة الاعداد
باحث / هبه عبد الحليم محمد عبد الحليم
مشرف / عادل صلاح خطاب
مشرف / حلمى رشاد مطاوع
مشرف / شريف عبد الونيس جبر
الموضوع
Animal Production.
تاريخ النشر
2018.
عدد الصفحات
102 p. :
اللغة
الإنجليزية
الدرجة
الدكتوراه
التخصص
الزراعية والعلوم البيولوجية (المتنوعة)
تاريخ الإجازة
20/2/2019
مكان الإجازة
جامعة طنطا - كلية الزراعة - Animal Production
الفهرس
Only 14 pages are availabe for public view

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from 129

Abstract

The present study was carried out on the Zaraibi, Baladi and Damascus herds kept in Sakha experimental station located in Kafr el-shikh governorate, Egypt. The station belongs to Animal Production Research Institute, Agriculture Research Center. Data used in this study included 871 records obtained from 504 does. Data were collected from years 2003 to 2017. The objectives of this study were: 1. Study different factors affecting litter size in goats, 2. Estimate genetic parameters of litter size trait for the studied goat breeds 3. Assess the genetic and phenotypic trends in order to evaluate the current breeding programs, 4. Investigate the polymorphism of GDF9 and FSHβ fecundity genes by PCR-RFLP technique in three goat breeds in Egypt (Zaraibi, Baladi and Damascus) and their association with litter size Data were analyzed using general linear model (GLM procedure) of SAS 2002. Animal model analysis used to estimate variance and covariance components, Three models were used , model 1, including, the fixed effects of breed, season of breeding , year of kidding and age of doe and their interactions and the random effects of animals, and errors. Model 2 is similar to model 1 in addition to the random effect of permanent environmental effect and Model 3 is similar to model 2 in addition to the random effect of maternal genetic effect and covariance between the direct and maternal genetic effect. the most suitable model. Blood samples were collected from the virgule vein of 120 does from three breeds; Zaraibi (n=40), Baladi (n=40) and Demascus (n=40), The does were selected according to their lit pedigree records. Each breeds was assembled into two groups; prolific (two or more kids per litter, n=20) and non-prolific (one kid per litter, n=20) . The genomic DNA was extracted from the whole blood, encoding GDF 9 and FSH ( exon 1) was amplified, purified and sequenced. Analyses of data showed that: - Multiple births were recorded in 48.81% of Zaraibi goats (Twins: 42.11%; triple:6.22% and quadruplets: 0.48%). The birth type ratios in Baladi goats were 57.89, 36.84, 5.26 and 0% for single, twins, triplets and quadruplets, respectively .On the other hand, most of Damascus goats (93.22%) gave only one kid - This study has shown the importance of some non-genetic factors on litter size at birth which could be accounted for genetic evaluations. - The least square means of litter size were 1.15±0.4, 1.42±0.25 and 1.54±0.20 for Damascus, Baladi and Zaraibi does, respectively. - The results indicated that Model 3 which including permanent enviromental and maternal genetic effects was the most appropriate model for estimates of variance components for litter size at birth. - Genetic correlation between direct and maternal genetic effects was positive being 0.64 ±0.07. - Heritability estimates obtained from LSB in this study were low (0.02), indicating that selection for LSB will take a long time. The speed and efficiency of selection is expected to increase by use of these molecular markers in selection. Alternative selection method (Marker Assisted selection) with higher accuracy in prediction of breeding value can be adopted for this trait. - In current study ,genetic trend for litter size was positive and significant for litter size trait,, but phenotypic trend in Damascus , Baladi and Zaraibi goat breeds were negative, not significant and being – 0.066, -0.063 and - 0.034 kid/ year , respectively . Optimal environmental conditions should be provided to obtain more genetic potential in order to coincidence of phenotypic trend with genetic one. - In Baladi goat breed, polymorphic restriction pattern indicate presence of one band with 710 bp among all lower litter size does and three bands with 710 and 600 bp and 100 bp for higher litter size does. These result showed that presence of polymorphic of GDF9 in Baladi goat which product twinning. - Zaraibi goat breed polymorphic restriction pattern indicate presence of one band with 700bp among all lower litter size does and two bands with 600 bp and 100 bp for higher litter size does. These result showed that presence of monomorphic of GDF9 in Zaraibi goat which product twinning. - None of the tested Baladi and Zaribi breed which produce single carried the GDF9 gene mutation in exon 1. - In Baladi and Zaraibi goat breeds, polymorphic restriction pattern indicate presence of one band with 202 bp among all lower and higher litter size does and none of the all tested does carried the FSHβ gene mutation in exon 1. PCR-RFLP analysis at the FSHβ gene with Pst1 restriction enzyme to digest the amplified fragment but this enzyme doesn’t digest the DNA amplified fragment. Future experiments directed to new mutants and its relations to fecundity in Egyptian goats may be required. -The results indicated that none of the tested individuals carried the FSHβ and GDF9 genes mutation in exon 1.in Damascus breed - Sequence analysis for GDF9ss in Baladi and Zaraibi breed shown no polymorphism in region between nucleotide 1 and 50 at amplified sequence of exon 1, so this region is consider as a highly conserved among alleles. CCGAGG transition of GTTCAT in region from 52 to 57 in high prolific sample sample. Transition of AG in the same samples in region 61-62. Also, sequence analysis for FSHβ revealed transition for CTGTT to ACAAA in region from 31 to 35 in all high prolific sample .These nucleotide changes associated with amino acid substitution. Amino acid substitutions were detected and repeated in higher and lower litter size animals, which can be used as marker-assisted selection for litter size trait in the goat breeds under study. Since, small ruminants, particularly goats are one of the expected livestock species that serve as income sources of farmers; emphases should be given by researchers and decision makers to improve their performance. Since prolificacy related molecular studies are meager in Egyptian goats, the observations made in this study will provide a base for more research on this line, in the future.