كليدواژه :
رﺷﺪ ﺟﻨﻴﻦ , ﻧﻴﺮوﻫﺎي ﻣﻜﺎﻧﻴﻜﻲ , ﺣﺮﻛﺎت ﺳﻠﻮﻟﻲ , ﺷﻜﻞ زاﺋﻲ
چكيده فارسي :
در اﺑﺘﺪا، ﺟﻨﻴﻦ ﺟﻠﻮ ﻳﺎ ﻋﻘﺐ، ﺳﺮ و دم ﻧﺪارد . ﻳﻚ ﮔﻮي ﺳﺎده از ﺳﻠﻮل ﻫﺎ اﺳﺖ ﻛﻪ ﺑﺰودي ﺷﺮوع ﺑﻪ ﺗﻐﻴﻴﺮاﺗﻲ ﻣﻲ ﻛﻨﺪ. ﻣﺠﻤﻮﻋﻪ ﻫﺎي ﺳﻠﻮﻟﻲ ﺑﻪ ﺷﻜﻞ ﺻﻔﺤﺎت ﺳﻠﻮﻟﻲ ﺑﻪ ﺳﺒﻚ اورﻳﮕﺎﻣﻲ ﺗﺎ ﻣﻲ ﺷﻮﻧﺪ و اﻧﺪاﻣﻬﺎي اوﻟﻴﻪ را ﻣﻲ ﺳﺎزﻧﺪ. ﻫﻴﭻ ﻳﻚ از اﻳﻨﻬﺎ ﻧﻤﻲ ﺗﻮاﻧﺪ ﺑﺪون ﻧﻴﺮوﻫﺎﻳﻲ ﻛﻪ ﺣﻴﻮان در ﺣﺎل رﺷﺪ را ﺗﺤﺖ ﻓﺸﺎر ﻗﺮار ﻣﻲ دﻫﻨﺪﻧﻤﻲ ﺗﻮاﻧﻨﺪ ﺷﻜﻞ ﻳﺎﺑﻨﺪ. ﺣﺘﻲ در ﺧﺎل ﺑﻠﻮغ ﺳﻠﻮل ﻫﺎي ﻳﻚ ارﮔﺎﻧﻴﺴﻢ ﺑﻪ ﻓﺸﺎر و ﻛﺸﻴﺪن ﺗﻮﺳﻂ ﻳﻜﺪﻳﮕﺮ و از ﻃﺮف ﻣﺤﻴﻂ اداﻣﻪ ﻣﻲ دﻫﻨﺪ. ﻧﺤﻮه ﺷﻜﻞ ﮔﻴﺮي ﺑﺪن و ﺑﺎﻓﺖ ﻫﺎ »ﻳﻜﻲ از ﻣﻬﻢ ﺗﺮﻳﻦ و ﻫﻨﻮز ﻧﺎﺷﻨﺎﺧﺘﻪ ﺗﺮﻳﻦ ﺳﺆاﻻت زﻣﺎن ﻣﺎ« ﺑﺮاي زﻳﺴﺖ ﺷﻨﺎﺳﺎن اﺳﺖ. ﺑﺮاي دﻫﻪ ﻫﺎ، زﻳﺴﺖ ﺷﻨﺎﺳﺎن ﺑﺎ ﺗﻤﺮﻛﺰ ﺑﺮ ﻣﻄﺎﻟﻌﻪ ژن ﻫﺎ و ﺳﺎﻳﺮ ﻣﻮﻟﻜﻮل ﻫﺎي زﻳﺴﺘﻲ ﺑﺪن ﺑﻪ ﻛﻤﻚ اﺑﺰار ﺗﺠﺰﻳﻪ و ﺗﺤﻠﻴﻞ در دﺳﺘﺮس ﺑﺮاي ﻣﻄﺎﻟﻌﻪ اﻳﻦ ﺳﻴﮕﻨﺎل ﻫﺎ، ﺑﻪ ﻧﻴﺮوﻫﺎي ﻣﻜﺎﻧﻴﻜﻲ دﺧﻴﻞ ﺑﺴﻴﺎر ﻛﻤﺘﺮ ﺗﻮﺟﻪ ﻛﺮده اﻧﺪ.
چكيده لاتين :
At first, an embryo has no front or back, head or tail. It’s a simple sphere of cells. But soon enough, the smooth clump begins to change. Fluid pools in the middle of the sphere. Cells flow like honey to take up their positions in the future body. Sheets of cells fold origami-style, building a heart, a gut, a brain. None of this could happen without forces that squeeze, bend and tug the growing animal into shape. Even when it reaches adulthood, its cells will continue to respond to pushing and pulling — by each other and from the environment. Yet the manner in which bodies and tissues take form remains “one of the most important, and still poorly understood, questions of our time”, says developmental biologist Amy Shyer, who studies morphogenesis at the Rockefeller University in New York City. For decades, biologists have focused on the ways in which genes and other biomolecules shape bodies, mainly because the tools to analyse these signals are readily available and always improving. Mechanical forces have received much less attention.
