Gamete types, sex determination and stable equilibria of all-hybrid populations of diploid and triploid edible frogs (Pelophylax esculentus).
Gamete types, sex determination and stable equilibria of all-hybrid populations of diploid and triploid edible frogs (Pelophylax esculentus).
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DOI：
10.1186/1471-2148-9-135
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发表时间：
2009-06-15
影响因子：
3.4
通讯作者：
Christiansen DG
中科院分区：
文献类型：
--
作者：
Christiansen DG
三倍体个体在杂交物种形成中通常起着关键作用。因此，了解配子类型（倍性和基因组含量）和三倍体个体的杂交群体的稳定性对于探索杂交在进化中的作用具有重要意义。食用蛙（Pelophylax esculentus）的全杂交种群在其组成和遗传动态方面是独特的：二倍体（基因型LR）和三倍体（LLR和LRR）杂交种依赖于彼此不同的配子贡献来成功繁殖和维持种群，因为亲本基因型Lessonae（LL）和P. ridibundus（RR）在成年人中不存在。这项研究提供了关于配子类型和性别决定的数据和解释，这对于理解这个有趣系统的功能，进化潜力和威胁至关重要。通过对一个杂交实验中的变态进行解剖，证实了性别决定是一个XX-XY系统，Y染色体局限于L染色体组。从杂交亲本和后代的微卫星分析，配子频率可以推断：两性三倍体大多数产生单倍体配子，其基因组在双倍剂量，但LLR雌性也产生约10%的LL配子通过自融合。LR蛙在配子产生方面表现出很大的差异。在LRR丰富的人群中，他们的LR精子产量足够高（22%）来解释观察到的LRR男性比例，其形成以前没有被理解。根据所得到的配子比例，建立了一个模型，计算了不同群体类型的平衡基因型比例，这些平衡与经验文献数据吻合得很好。如果基因型比例的种群分化真的是由配子模式驱动的，正如本研究所强烈建议的那样，全杂交种群构成的不是一个，而是几个本质上不同的育种系统。如果雄性和雌性的存活率或生育力都增加，则可能发生四倍化。在没有进一步了解非杂交体不活力背后的机制的情况下，不能预测杂交体或亲本物种个体的引入是否会威胁全杂交体种群，但至少预测具有Y因子的R基因组如果引入，将是侵入性的，并且可能使种群崩溃。
Triploid individuals often play a key role in speciation by hybridization. An understanding of the gamete types (ploidy and genomic content) and stability of hybrid populations with triploid individuals is therefore of importance for exploring the role of hybridization in evolution. The all-hybrid populations of the edible frog, Pelophylax esculentus, are unique in their composition and genetic dynamics: Diploid (genotype LR) and triploid (LLR and LRR) hybrids depend on each other's different gamete contributions for successful reproduction and maintenance of the populations, as the parental genotypes P. lessonae (LL) and P. ridibundus (RR) are absent among adults. This study provides data and interpretations on gamete types and sex determination that are essential for understanding the function, evolutionary potential and threats of this intriguing system. Dissection of metamorphs from a crossing experiment confirmed that sex determination is an XX-XY system with the Y confined to the L genome. From microsatellite analysis of parents and offspring from the crossings, gamete frequencies could be deduced: Triploids of both sexes mostly made haploid gametes with the genome they had in double dose, however LLR females also made approximately 10% LL gametes by automixis. LR frogs showed much variation in their gamete production. In LRR-rich populations, their LR sperm production was sufficiently high (22%) to explain the observed proportion of LRR males, the formation of which has not previously been understood. A model was constructed to calculate equilibrium genotype proportions for different population types on the basis of the gamete proportions found. These equilibria agreed well with empirical literature data. If population differentiation with respect to genotype proportions is really driven by gamete patterns, as strongly suggested by the present study, all-hybrid populations constitute not one, but several intrinsically different breeding systems. Tetraploidization could occur if the survival or fertility of both males and females increased. Whether introduction of hybrid or parental species individuals would threaten the all-hybrid populations cannot be predicted without further knowledge on the mechanisms behind non-hybrid inviability, but at least R genomes with Y factor are predicted to be invasive, if introduced, and could bring the populations to collapse.
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影响因子：
1.6
作者：
BERGER L;BERGER W A
通讯作者：
BERGER W A
DOI：
10.1098/rstb.2008.0048
发表时间：
2008-09-12
影响因子：
6.3
作者：
Cunha, Carina;Doadrio, Ignacio;Coelho, Maria M.
通讯作者：
Coelho, Maria M.
影响因子：
2.1
作者：
HILLIS, DM;GREEN, DM
通讯作者：
GREEN, DM
DOI：
10.1111/j.1471-8286.2004.00869.x
发表时间：
2005-03-01
期刊：
MOLECULAR ECOLOGY NOTES
影响因子：
--
作者：
Christiansen, DG
通讯作者：
Christiansen, DG
影响因子：
2.4
作者：
Engeler, B;Reyer, HU
通讯作者：
Reyer, HU