GENETIC ANALYSIS OF THE MORPHOLOGICAL DIFFERENCES BETWEEN TWO INTERFERTILE SPECIES OF HAWAIIAN DROSOPHILA
GENETIC ANALYSIS OF THE MORPHOLOGICAL DIFFERENCES BETWEEN TWO INTERFERTILE SPECIES OF HAWAIIAN DROSOPHILA
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夏威夷果蝇两个不育种之间形态差异的遗传分析
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发表时间：
1977
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通讯作者：
Francisca C. do Val
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作者：
Francisca C. do Val
在自然界和实验室中，大多数生物物种在生殖上与其最近的亲属隔离。因此，直接分析它们之间的遗传差异是不可能的孟德尔的方法。关于物种之间遗传差异程度的推断可以基于比较生物化学研究（例如Ayala，1974）或基于多线染色体测序（克莱顿等人，1972年）。然而，在某些非常接近的物种的关键情况下，这两种技术都没有用。已知形态学和行为学上不同的物种不能通过等位酶或染色体区分（卡森等人，1975年）。事实上，人类和黑猩猩等明显遥远的物种之间的生化相似性导致人们假设调节基因而不是结构基因是物种之间重要生物学差异的基础（King和Wilson，1975）。我在这里报告的结果杂交实验之间的两个形态和行为不同物种的夏威夷果蝇。通过使用克服行为隔离的方法，有可能获得两性都能育的正反交杂种（Ahearn和瓦尔，1975）。F2和回交揭示了形态学上相当大的分离多基因差异。这些物种表现出密切的细胞学和电泳相似性。因此，我相信观察到的性状分离代表了调节形态的多基因，而不是染色体序列或结构蛋白的差异。本研究中考虑的物种是异脉果蝇（Drosophila heteroneura）（Perkins，1910）和森林果蝇（Drosophila silvestris）（Perkins，1910）。它们是夏威夷岛的特有种，在那里它们在许多地方是同域分布的。它们属于一群夏威夷图片翅果蝇的平胫亚群中的同源物种。这一集群的不同方面是最近几项研究的主题。该物种构成了卡森染色体发生学中的一个末端分支（克莱顿等人，1972年）。目前，有四个种被认为属于它：来自莫洛凯岛的不同种哈代和Kaneshiro（1975）;来自毛伊岛的扁尾亚目哈代（1966）;来自夏威夷岛的异脉亚目和银尾亚目。D. Differences是最近描述的一个新种，Ahearn et al.（1974）、Craddock（1974 a，B）和约翰逊et al.（1975）将其称为来自莫洛凯岛的类扁形菌。卡森（1970）、卡森等人（1970）、卡森（1974）、克拉多克（1974 a，B）讨论了这一物种群中的物种形成，Kaneshiro（正在准备中）的大量工作也是这个主题。D. heteroneura和D. silvestris构成同域种的一个例子，从这种同域种中可以在实验室中相对容易地获得正反两个方向的可育杂种。交配前障碍是造成它们之间生殖隔离的原因，这在Ahearn et al.（1974）的行为隔离研究中已经得到证实，Craddock（1974 a，B）也对此进行了讨论。雄性和雌性实验室杂种的完全生育力使这些物种适合研究物种差异的遗传。
Most biological species are reproductively isolated from their closest relatives both in nature and in the laboratory. Thus direct analysis of the genetic differences between them is not possible by Mendelian methods. Inferences as to the extent of genetic differences between species can be based on comparative biochemical studies (e.g. Ayala, 1974) or on polytene chromosome sequencing (Clayton et al., 1972). In key instances of certain very close species, however, both these techniques fail to be useful. Morphologically and behaviorally distinct species are known which cannot be distinguished either by allozymes or chromosomes (Carson et al., 1975). Indeed, the biochemical similarity between such obviously distant species as man and chimpanzee have led to the postulating of regulatory rather than structural genes as the basis of the important biological differences between species (King and Wilson, 1975). I report here the results of hybridization experiments between two morphologically and behaviorally distinct species of Hawaiian Drosophila. By using methods to overcome ethological isolation, it is possible to obtain reciprocal hybrids which are fertile in both sexes (Ahearn and Val, 1975). F2's and backcrosses reveal considerable segregating polygenic differences in morphology. These species show close cytological and electrophoretic similarity. Accordingly, I believe that the character segregations observed represent polygenes regulating morphology rather than differences in chromosome sequences or in structural proteins. The species considered in the present work are Drosophila heteroneura (Perkins, 1910) and Drosophila silvestris (Perkins, 1910). They are endemic to the Island of Hawaii where they are sympatric in many localities. They belong to a cluster of homosequential species of Hawaiian picture-winged Drosophila in the planitibia subgroup. Different aspects of this cluster have been the subject of several recent studies. The species constitute one of the end branches in Carson's chromosome phylogeny (Clayton et al., 1972). At the present time, four species are considered to belong to it: differens Hardy and Kaneshiro (1975), from Molokai; planitibia Hardy (1966), from Maui; heteroneura and silvestris from the Island of Hawaii. D. differens, just recently described as a new species, was referred to as planitibialike from Molokai by Ahearn et al. (1974), Craddock (1974a,b) and Johnson et al. (1975). Speciation in this cluster of species has been discussed in Carson (1970), Carson et al. (1970), Carson (1974), Craddock (1974a,b) and is the subject of an extensive work by Kaneshiro (in preparation). D. heteroneura and D. silvestris constitute a case of sympatric species from which fertile hybrids in both reciprocal directions can be obtained in the laboratory with relative facility. Premating barriers are responsible for reproductive isolation between them, as has been shown in a study of their ethological isolation by Ahearn et al. (1974), and discussed by Craddock (1974a,b). The full fertility of male and female laboratory hybrids makes these species suitable for studying the inheritance of species differences.