Hybrid lizards with introgressed mtDNA show increased resistance to DNA damage from Reactive Oxygen Species

Hybrids can experience genetic incompatibilities that lead to cellular dysfunction and infertility. Previous analyses of mitochondrial function in the lizards Urosaurus graciosus and Urosaurus ornatus found that hybrids, which had introgressed mtDNA, experienced higher ATP production which increases reactive oxygen species (ROS) production, one of the main causes of damage to DNA. Hybrid populations of these lizards have persisted so we predicted they may have mechanisms for protecting their DNA from damage. To test this, we exposed liver cells of these lizards to hydrogen peroxide, a source of ROS, and compared DNA damage using single-cell gel electrophoresis. Hybrid cells showed significantly less DNA damage. We then examined potential mechanisms to explain this result by comparing melanin content of livers and expression levels of antioxidant genes. If functioning to deal with ROS, these should be expressed higher in hybrids. Melanin content of livers was highly variable among U. gra..., Urosaurus graciosus and U. ornatus lizards were sampled from 2 different populations of each type of lizard at the following locations in Arizona during June 2020 (AZ permit #SP403988, IACUC Protocol #2019-0001): U. ornatus morphology and mtDNA n = 4: Burro Creek (n = 2, -113o 27.00W, 34o32.55N), Wickenburg Wash (n = 2, -112° 42' 39.13W, 33° 57' 2.12N); U. graciosus morphology with U. ornatus mtDNA “Hybrid ” n = 5: Detritial Wash (n = 3, -114o30.84W, 35o49.06N), Date Creek (n = 2, -113o9.966W, 34o9.160N), U. graciosus morphology and mtDNA n = 5: Walnut Creek (n = 3, - 114o9.619W, 35o2.17N), Hassayampa Wash (n = 2, -112° 40' 54.35\"W, 33° 44.35\"N).
MtDNA type was verified using a three primer species specific PCR protocol that amplifed either a 81 bp fragment from U. ornatus/hybrid type mtDNA from the ND1 gene or a 141 bp fragment from U. graciosus type mtDNA (see Haenel and Del Gaizo Moore, 2018 for details). The conserved reverse primer was 5’-GGTCGTACTGGTTCTTTTGTGAATA-3’, the U. ornatu..., , # Hybrid lizards with introgressed mtDNA show increased resistance to DNA damage from Reactive Oxygen Species

[https://doi.org/10.5061/dryad.mgqnk9962](https://doi.org/10.5061/dryad.mgqnk9962)

## Description of the data and file structure

File: **Olive_moment_data.csv**

data table in csv format

Olive_moment_data: This sheet contains the 100 (or fewer if less than 100 available) randomly selected olive moment data for each individual.

Column names

Species: lizard type Ug = Urosaurus graciosus, Uo = Urosaurus ornatus, Hyb = hybrids between the two species

ID: individual identifier for each individual

Olive_Moment: Olive moment value calculated from OpenComet relative to the average control for that individual.

**Location of samples**

Species ID long lat

Hybrid 455 -114° 30.84W, 35° 49.06N

Hybrid 1033 -114° 30.84W, 35° 49.06N

Hybrid 1203 -114° 30.84W, 35° 49.06N

Hybrid 1335 -113° 9.966W, 34° 9.160N

Hybrid 2152 -113° 9.966W, 34° 9.160N

Urosaurus graciosus 523 -1...,

杂交个体可能遭遇遗传不相容性，进而引发细胞功能障碍与不育。此前针对峡边蜥属蜥蜴优雅峡边蜥（Urosaurus graciosus）与饰纹峡边蜥（Urosaurus ornatus）的线粒体功能分析显示，携带渐渗线粒体DNA（mitochondrial DNA, mtDNA）的杂交个体，其三磷酸腺苷（adenosine triphosphate, ATP）生成量更高，而这会增加活性氧（reactive oxygen species, ROS）的产生——活性氧是引发DNA损伤的主要诱因之一。此类蜥蜴的杂交种群仍能存续，因此我们推测它们可能具备保护DNA免受损伤的机制。为验证这一假设，我们将这些蜥蜴的肝细胞暴露于活性氧源过氧化氢中，并通过单细胞凝胶电泳（single-cell gel electrophoresis）比较各组的DNA损伤程度。结果显示，杂交细胞的DNA损伤程度显著更低。随后，我们通过比较肝脏的黑色素含量与抗氧化基因的表达水平，探究了可解释该结果的潜在机制：若相关机制用于应对活性氧，那么这些基因在杂交个体中的表达量应更高。肝脏黑色素含量在U. gra..., 中存在高度变异。本研究于2020年6月在亚利桑那州的以下地点，为每种蜥蜴从2个不同种群中采集样本（亚利桑那州许可编号SP403988，实验动物护理和使用委员会协议编号2019-0001）：
饰纹峡边蜥（U. ornatus）形态且携带对应线粒体DNA：样本量n=4，分别来自Burro Creek（n=2，坐标-113°27.00W，34°32.55N）与Wickenburg Wash（n=2，坐标-112°42'39.13W，33°57'2.12N）；携带饰纹峡边蜥线粒体DNA的优雅峡边蜥形态个体（即"杂交个体"）：样本量n=5，分别来自Detritial Wash（n=3，坐标-114°30.84W，35°49.06N）与Date Creek（n=2，坐标-113°9.966W，34°9.160N）；优雅峡边蜥（U. graciosus）形态且携带对应线粒体DNA：样本量n=5，分别来自Walnut Creek（n=3，坐标-114°9.619W，35°2.17N）与Hassayampa Wash（n=2，坐标-112°40'54.35"W，33°44.35"N）。
线粒体DNA类型通过三引物物种特异性聚合酶链式反应（polymerase chain reaction, PCR）方案进行验证：该方案可扩增出饰纹峡边蜥/杂交型线粒体DNA ND1基因的81 bp片段，或优雅峡边蜥型线粒体DNA的141 bp片段（详细方法参见Haenel与Del Gaizo Moore, 2018）。保守反向引物序列为5’-GGTCGTACTGGTTCTTTTGTGAATA-3’，U. ornatu...,

# 携带渐渗线粒体DNA的杂交蜥蜴对活性氧引发的DNA损伤表现出更强抗性
[https://doi.org/10.5061/dryad.mgqnk9962](https://doi.org/10.5061/dryad.mgqnk9962)

## 数据与文件结构说明
文件：**Olive_moment_data.csv**
该文件为CSV格式的数据表。
Olive_moment_data：该数据表包含每个个体随机选取的100条（若可用样本不足100则为对应数量）橄榄矩（Olive Moment）数据。
列名说明：
- Species：蜥蜴类型，Ug代表优雅峡边蜥（Urosaurus graciosus），Uo代表饰纹峡边蜥（Urosaurus ornatus），Hyb代表二者的杂交个体
- ID：每个个体的唯一标识符
- Olive_Moment：通过OpenComet软件计算得到的橄榄矩值，以对应个体的对照组平均值为基准进行标准化。

**样本采集地点**
Species ID long lat
Hybrid 455 -114° 30.84W, 35° 49.06N
Hybrid 1033 -114° 30.84W, 35° 49.06N
Hybrid 1203 -114° 30.84W, 35° 49.06N
Hybrid 1335 -113° 9.966W, 34° 9.160N
Hybrid 2152 -113° 9.966W, 34° 9.160N
Urosaurus graciosus 523 -1...,