Читать книгу Lifespan Development - Tara L. Kuther - Страница 145

Strapped in and buckled in the rear seat of her mother’s bicycle, 1-year-old Jenna patted her helmet as her mother zoomed along the bike path to the beach. There she giggled and kicked her legs as her mother whooshed her through the water. As a child, Jenna loved to be outside and especially in the water. Jenna practiced swimming at the local YMCA nearly every day and became quite skilled. Jenna’s proud mother encouraged her daughter’s athleticism by enrolling her in swim classes. As a teenager, Jenna decided that if she were going to become an exceptional swimmer, she would have to go to a summer swimming camp. She researched camps and asked her mother if she could attend. Jenna further honed her skills as a swimmer and won a college scholarship for swimming.

Many years later, Jenna was surprised to learn that she had a twin sister, Tasha. Separated at birth, Jenna and Tasha became aware of each other in their early 40s. Jenna was stunned yet couldn’t wait to meet her twin sister. Upon meeting, Jenna and Tasha were surprised to find that they were not exactly the same. Whereas Jenna was athletic and lithe, Tasha was more sedentary and substantially heavier than Jenna. Unlike Jenna, Tasha grew up in a home far from the beach and with little access to outdoor activities. Instead, Tasha’s interest was writing. As a child, she’d write stories and share them with others. She sought out opportunities to write and chose a college with an exceptional writing program. Both Jenna and Tasha excelled in college, as they did throughout their education, and earned nearly identical scores on the SAT.

Jenna and Tasha look very similar. Even the most casual observer could easily tell that they are sisters as both have blond hair, blue eyes, and a similar facial structure. Tasha’s skin, however, is more fair and unlined. Jenna’s face is sprinkled with freckles and darker spots formed after many days spent swimming outside. Jenna and Tasha both are allergic to peanuts, and they both take medication for high blood pressure. The more that Jenna and Tasha get to know each other, the more similarities they find.

1 Considering Jenna and Tasha, provide examples of three types of gene–environment correlations: passive, evocative, and active.

2 Do you think Jenna and Tasha are monozygotic or dizygotic twins? Why or why not?

3 What role might epigenetic influences play in determining Jenna and Tasha’s development?