Chapter 10 - Differentiation and gene expression

  • strict warning: Non-static method view::load() should not be called statically in /var/www/pia/drupal/sites/all/modules/views/views.module on line 906.
  • strict warning: Declaration of views_handler_argument::init() should be compatible with views_handler::init(&$view, $options) in /var/www/pia/drupal/sites/all/modules/views/handlers/views_handler_argument.inc on line 744.
  • strict warning: Declaration of views_handler_filter::options_validate() should be compatible with views_handler::options_validate($form, &$form_state) in /var/www/pia/drupal/sites/all/modules/views/handlers/views_handler_filter.inc on line 607.
  • strict warning: Declaration of views_handler_filter::options_submit() should be compatible with views_handler::options_submit($form, &$form_state) in /var/www/pia/drupal/sites/all/modules/views/handlers/views_handler_filter.inc on line 607.
  • strict warning: Declaration of views_handler_filter_boolean_operator::value_validate() should be compatible with views_handler_filter::value_validate($form, &$form_state) in /var/www/pia/drupal/sites/all/modules/views/handlers/views_handler_filter_boolean_operator.inc on line 159.
  • strict warning: Declaration of views_plugin_style_default::options() should be compatible with views_object::options() in /var/www/pia/drupal/sites/all/modules/views/plugins/views_plugin_style_default.inc on line 24.
  • strict warning: Declaration of views_plugin_row::options_validate() should be compatible with views_plugin::options_validate(&$form, &$form_state) in /var/www/pia/drupal/sites/all/modules/views/plugins/views_plugin_row.inc on line 134.
  • strict warning: Declaration of views_plugin_row::options_submit() should be compatible with views_plugin::options_submit(&$form, &$form_state) in /var/www/pia/drupal/sites/all/modules/views/plugins/views_plugin_row.inc on line 134.
  • strict warning: Only variables should be passed by reference in /var/www/pia/drupal/modules/book/book.module on line 559.
Printer-friendly version

figure

Ripening of fruit such as tomato involves a tightly regulated sequence of physiological transitions and changes in expression of several genes, with the plant hormone ethylene playing a coordinating role. The visible colour change from green to red is due to chlorophyll degradation and synthesis of red lycopene pigment. Around this time respiration rate increases, ethylene synthesis accelerates, cell wall softening genes are expressed aroma and flavour compounds are synthesised, and acids and starch are converted to sugars. Overall this packaging is an attractive food to many animals and the benefit to the plant is increased probability of seed dispersal.

(Photograph courtesy J.D. Hamill)

Simply, the organism is a unique result of both its genes and the temporal sequence of environments through which it has passed, and there is no way of knowing in advance, from the DNA sequence, what the organism will look like, except in general terms.

(R.C. Lewontin (1997) 'Genes, environment, and organisms', Hidden Histories of Science, ed. R.B. Silvers, 115-140, Granta Books: London)

»