How to Grow Butter Leaf Lettuce. Butter lettuce is a loose-leaf lettuce with a mild flavor. Lettuce is a cool-weather crop, grown across the U.S. in the spring and fall when temperatures are moderate. Butter lettuce, a loose-leaf type of lettuce, may be more tolerant of hot temperatures than some other varieties. In maritime climates with cool summers, lettuce may be grown in the summer, fall and late winter. Inland, where temperatures rise in the summer, lettuce may be grown in late winter and fall.
Humans have 23 pairs of chromosomes, one half of each pair inherited from each parent. The Y chromosome is small, carries few genes, and has abundant repetitive sequence, while the X chromosome is more autosome-like in form and content.
1 47 XYY syndrome: A genetic condition where males have an extra Y chromosome in each of their cells. 2  Normally male cells have one X and one Y chromosome.3  This is not usually an inherited condition but a defect that occurs during cell division.4  Often the condition is asymptomatic. 47 XYY syndrome: A genetic condition where males have an extra Y chromosome in each of their cells. 2  Normally male cells have one X and one Y chromosome.