Sheep breeding is an ancient occupation in Palestine and its neighboring countries where it has been practiced for a thousand of years (Epstein, 1985). Improved Awassi was developed through breed selection and now the improved Awassi can be characterized by its high milk production (an average of 506 L/lactation) (Gootwine and Pollott, 2000). The improved Awassi have been distributed from Israel (the country of origin) to many countries around the world (Rummel et al., 2005). Sheep population in Jordan was estimated to be 2.5 million heads; the majority of this population is Awassi sheep that is the most dominant breed of sheep found in Jordan. In addition to the Improved Awassi that was imported from Israel starting from 1999 (MOA, 2008), some exotic breeds were imported from outside Jordan, such as Suffolk, Romanov Charollais, that reared for research purposes at Jordan University of science and Technology (JUST).

The improved Awassi in Israel can be found only in Ein Harod (the origin flock) which is the main source of this line of Awassi, and as Gootwine et al. (2008) reported that for several decades the Ein Harod dairy flock has been a closed flock. Only five Booroola Merino rams as foreign genetic material was introduced once in 1986, except this exotic rams, the replacement were selected from the same flock for several decades, which lead to increase the inbreeding that play a vital role in manifestation of undesired recessive traits, Shamir et al. (2010) showed the segregation of a novel recessive mutation that cause day blindness in Improved Awassi and recently Reicher et al. (2010) found the mutation that cause the day blindness in Awassi sheep, which is located in the CNGA3 gene that codes for the cone photoreceptor cyclic nucleotide-gated channel subunit α. Komáromy (2010) investigate the necessity of the availability of large animal models for both CNGA3- and CNGB3-achromatopsia for translational purposes, while Kohl et al. (2005) shows that the majority of achromatopsia disease patients mainly affected by the mutations in these two genes (that are responsible for the disease). The mutation in CNGA3 gene affects negatively sheep breeding programs (increasing culling percentage). The distribution of improved Awassi through breeding station and stock owners flocks as well (MOA, 2008) may have a high contribution in distributing of some rams from the stations to farmers fields that may carry the undesired mutation of day blindness, and the eradication of this mutation from the breeding stations is the main step that can be done in order to avoid spreading of this mutation through breeding flocks and farmers flocks as well.

The main objective of this paper is to estimate the genotype and allele frequencies of the day blindness mutation in the improved and cross bred (Local×Improved) Awassi ram in the Hashemite kingdom of Jordan.

The amplification of CNGA3 gene in PCR produced 107 bp band, while the digestion of this product by AvaII restriction enzyme harvest genotypes: homozygous normal-vision (RR) lamb; A major band of 41+45 bp and a minor band of 21 bp were detected. Heterozygous carrier (RS) lamb; Major bands of 66 bp and 41+45 bp were detected, along with a faint minor band of 21 bp (Figure 1). The homozygous day-blind lamb; Two major bands that supposed to be detected that reported by Reicher et al. (2010) to have one of 66 bp and the other of 41+45 bp. In our case no blind animals were genotyped because all blind born lambs culled early from the stations or flocks.

Out of 423 genotyped rams, 74 rams were found to be carriers for the mutation. Mutated allele and genotype frequencies (RS) were 0.088 and 17.49%, respectively (Table 1).

In stations this mutation has been identified to be with high RS (0.121%) and genotype frequency (24.15%) compared with lower frequencies in farmers’ fields (Table 1). This mutation was higher at Al-Khanasry and Al-Mushairfa stations compared to Al-Fjaje station (Table 1). The distribution of improved rams to the farmers (the strategy of Ministry of Agriculture) for genetic improvement of the local Awassi breed may have a substantial contribution in the distribution of this mutation in private flocks, but still in low level compared with the situation in the breeding stations (Table 1).

The frequency of day blindness mutation in Jordan was higher than that reported by Shamir et al. (2010) (1.7%) in Israeli improved Awassi flocks. The mutated allele (RS) frequency in Jordan was lower than RS frequency in Israeli improved ram (0.35) and ewes (0.25) that genotyped at the Volcai Center (unpublished data). The only work that conducted in day blindness of improved Awassi that published by the Israeli group (Shamir et al., 2010; Reicher et al., 2010).

The distribution of the improved Awassi rams through breeding stations and farmers flocks has been detected as main risk factors for the distribution of the mutation within Awassi flocks.

Eradication program must be continued in order to decrease the frequency of the unfavorable allele in breeding station as the first step that can be lead to avoiding having such affected rams in farmer’s fields.

Allele and genotype frequencies were high in Jordanian breeding stations and culling program must be adopted and maintained for the purpose of diminishing the rate of dispersion of this unfavorable mutation in governmental breeding stations and private sheep flocks.