BIOL 0170 Lecture Notes - Lecture 17: Preimplantation Genetic Diagnosis, Sex Selection, Blastocyst
28 Nov 2016
School
Department
Course
Professor
Document Summary
Difference in weight of sperm containing larger x (less energetic) vs. smaller y (more energetic: costs , 91% successful n producing female offspring, 76% for male, not widely used, most us parents opt for female offspring. Pgd (pre-implantation genetic diagnosis: pgd: take one cell from blastocyst (out of 8 cell mass) and do genetic testing. Usually used for tests of chromosomal and genetic disorders. Trisomy and monosomy often leads to miscarriage. Pgd has dual purpose here: increase likelihood of successful pregnancy, eliminate disease if aberrant chromosome carried to term. Blastocysts can be tested for over 100 single-gene disorders (cf, fragile x, tay- Sachs: pgd is essentially equivalent to amniocentesis except avoids risks of procedure, need for abortion, may avoid implantation of likely-to-miscarry blastocyst. Amniocentesis is preformed post-implantation: 10-20k children born from blastocysts selected by pgd since 1997. Raises question of biotechnology vs. bioethics: assumption in pgd that all 8 cells in blastocyst are identical.
