Preliminary Study on the Level of Evolutionary Differentiation between Domestic Quails and Wild Japanese Quails

This paper makes an analysis of the ecological behaviours of 3 categories of quails, namely wild Japanese quails from the Weishan Lake Area, medium-sized domestic quails and pint-sized domestic quails. The study indicates as follows: (1) There is difference in morphological and biological habits between domestic quails and wild Japanese ones. (2) The cross-breeding between the wild and domestic quails is a cross from exclusion to affinity. (3) The behaviours of quails such as pursuit,paw and mating are selective. (4) The wild Japanese quails and domestic ones can succeed in mating and in reproducing fertilized eggs but with a low rate. (5) Evolutionary differentiation has been formed in varying degrees between the domestic quails and their wild ancestors in morphological and ecological characteristics. (Asian-Aust. J. Anim. Sci. 2003. Vol 16, No. 2 : 266-268)


INTRODUCTION
Quails (Coturnit coturnix japonica), which belong to Coturnix, Phasianidae, Callifermes, Aves, have developed into two species in orient-Asia named Common quails (Coturnix coturnix) and Japanese quails (Coturnix Japanica) (Check-list of North American Birds, 1983;Chang, 1995). Domestic quails, derived from Japanese quails, as laying, meat and laboratory animals with special value, have produced a flourishing industry (Lin, 2000;Chang et al., 2001a). Revealing the level of the two species' evolutionary differentiation on ecological behaviours and hybrid fertility will help to strengthen the quail industry and promote effective protection and exploitation of quail genetic resources. It can also add to data about quails' behaviours, the phylogenetic relationship and systematic divergence between wild and domestic quails, and the domestic quails' changes during their domestication and improvement.

Materials, sampling methods
The experimental wild Japanese quails were captured during their migrate seasons from Weishan Lake Area on the borders of Jiangsu, Shandong and Anhui provinces (Chang et al., 2001). The domestic ones were obtained from a local aviary. After being vaccinated and accustomed to cage life, each quail was tested for body weight and size measure (Chang et al., 2000c) and then divided into groups, each group with one male to multiple females (Wechsler, domestication, some behaviours of domestic quails are still somewhat wild, such as nervousness, early maturity, selective mating, the male's tendency to fight.

The cross from exclusion to affinity
The exclusionary behaviours such as fighting and pecking took place at the initial stage of experiments. With the passage of time, the rate of their occurance declined and they were gradually replaced by pursuit, paw and mating. This does not demonstrate any obvious social hierarchy, i.e. selectiveness. It may be a process of adapting to each other. Of all these behaviours, fighting rarely occurs, which is perhaps attributed to group division because of the male's belligerant and gluttonous inclination to fight and feed (Xie, 1995).

Statistical analysis of pursuit, paw and mating
The results are shown in Table 2 and 3. From Tables 2  and 3, such analysis can be made.
Pursuit : The males pursued the pint-sized domestic females, the medium-sized domestic ones and the wild females in varying degrees of intensity. But there was no obvious difference among the three types of females (p>0.05). The medium-sized domestic males' pursuit frequency was higher than the other two males, but there was no difference between the latters. This indicates that body size is an obstacle to successful mating.
Paw : In general, there was no obvious difference between the medium-sized and pint-sized domestic male quails, that is, they have random selection for the females (p>0.05). The wild female quails have the least paw behaviours, substantially lower than the other two types of females (p<0.05), but no obvious difference was observed between the two types of females (p>0.05). Of all the crossing-groups, a 3 ×b 2 is the most active in pawing, distinctly higher than the others (p<0.01 or p<0.05) with the exception of a 1 ×b 1 .
Mating : The males have much higher mating frequency with the wild female than the other two females (p<0.05). Of all the crossing-groups, the highest mating frequency was observed in a 3 ×b 2 , showing significant difference from a 3 ×b 1 (p<0.05) and a 3 ×b 3 (p<0.01). There was no obvious difference between the domestic quails (p>0.05).
Statistics of laying (The results are shown in Table 4.) The quails generally lay eggs after noon, mostly after 15:30. According to Table 4, the fertility rate in W group was significantly lower than other groups (p<0.05).

DISCUSSION
The statistical results of pursuit, paw and mating show that the spouse choosing inclination gradually increases. The wild male did not show a significant difference in pursuing the pint-sized domestic females, but reflects significant affinity in paw and mating. The data also show a relatively lower ethological isolation between the wild and the pint-sized domestic quails than other groups. This is probably due to the little difference in size and the lower level of evolutionary differentiation between them. There is no significant differentiation between the two domestic populations. In addition, the results of mating and laying indicate that mating is feasible between the domestic and wild quails and that gene exchange can take place under certain circumstances. But between the two colonies there has been formed differentiation in appearance and ecological characteristics, which to some extent has affected the crossbreeding fertility. The rate of successful mating needs to be clarified. Further research and discussions are required to account for the few behaviours of the wild females.
Fuzzy cluster analysis and polymorphism examination of encoding the enzymes in viscera and muscle show that there is a close phylogenteic relationship between the wild Japanese quails in Weishan Lake Area and the domestic quails. However, it has become estranged due to the longterm evolution (Akiko, 1994;Sano, 1995;Chang et al., 2001d). The study also indicates that the two populations have possessed a certain lower differentiation in terms of size, colour and biological characteristics. The lower evolutionary level of the wild and the pint-sized quails may have resulted in gene change in quail populations accidently carried by weight selection (Cheng et al., 1992;Zheng, 1994). There is no obvious divergence between the medium-sized and pint-sized domestic quails. The long-period domestication of quails has caused difference from the wild populations, but they still retain some wild characteristics (Lin, 2000). Ethological isolation has formed during the evolutionary course between the domestic quails and their wild ancestors, i.e. the Japanese quails. It may be one of the factors that such kind of genetic divergence boosts to form the mechanism of prezygotic RIM.  The same letters mean insignificant difference (p>0.05). The different letters mean significant difference (The capital letters represent p<0.01, otherwise, p<0.05). a 1 , a 2 , a 3 , b 1 , b 2 , b 3 respectively represents the Medium-sized domestic quails ( ), the Pint-sized domestic quails ( ), the Wild quails ( ), the Medium-sized domestic quails ( ), the Pint-sized domestic quails ( ) and the Wild quails ( ).