Title “Polymorphism analysis of BMP15 and GDF9 genes for litter size for marker-assisted selection in Bonga sheep” The objective of the work is as follows: General objective: To determine the polymorphism of fecundity genes in Bonga sheep Specific objectives: 1. To assess polymorphic sites on BMP15 and GDF9 genes associated with litter size in Bonga sheep 2. To evaluate the haplotype diversity and extent of linkage disequilibrium of detected loci in the BMP15 and GDF9 genes 3. To implement marker-assisted selection in the community-based breeding program of Bonga sheep This literature review work will be a continuation of the dissertation work which I will attach it later. The title is suggested as a future step in the poster (https://cgspace.cgiar.org/bitstream/handle/10568/109791/joram.pdf?sequence=1&isAllowed=y) and that is why this proposal is initiated. So, I only need a 15-page literature review with recent journal article citations for my proposal and I will attach other important dissertations and journal articles related to my research project. The outline of the literature review should be as follows: 1.Importance of fertility in sheep production 2.Reproductive traits of economic importance in sheep 2.1.Age at first lambing 2.2.Litter size 2.3.Lambing interval 3.Factors that affect fertility in sheep 3.1.Environmental and management factors 3.2.Genetic factors 4.Bonga breed as prolific sheep 5.Fecundity and fecundity genes in sheep 5.1.BMP15 gene 5.2.GDF9 gene 5.3.BMPR1B gene 6.Known variants of BMP15 and GDF9 genes and their effects 7.Genetic polymorphism 7.1.Polymorphism of BMP15 gene and its association with litter size in sheep 7.2.Polymorphism of GDF9 gene and its association with litter size in sheep 8.Marker-assisted selection in sheep If the writer thinks something is missed in my outline, he/she can add based on the above-mentioned objectives.