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.
Xyy redirects here. For the CIE XyY colour model, see XyY. XYY syndrome is a genetic condition in which a human male has an extra male (Y) chromosome, giving a total of 47 chromosomes instead of the more usual 46. This produces a 47,XYY karyotype, which occurs every 1 in 1,000 male births.yy redirects here. For the CIE XyY colour model, see XyY. XYY syndrome is a genetic condition in which a human male has an extra male (Y) chromosome, giving a total of 47 chromosomes instead of the more usual 46. This produces a 47,XYY karyotype, which occurs every 1 in 1,000 male births.