Chapter - 8.ppt-BB - 2012

Variation a a some members of a species a a segmental

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Unformatted text preview: the same species Inversions A chromosomal inversion is a segment that has been chromosomal flipped to the opposite orientation flipped In an inversion, the total amount of genetic information stays the same In In rare cases, inversions can alter the phenotype of an individual About 2% of the human population carries inversions that are detectable About with a light microscope with Inversion Heterozygotes Inversion Individuals with one Individuals copy of a normal chromosome and one copy of an inverted chromosome chromosome may be may phenotypically normal normal During meiosis I, During homologous chromosomes synapse with each other other Translocations A chromosomal chromosomal translocation occurs when a segment of one chromosome becomes attached to another attached In reciprocal translocations two nontranslocations homologous homologous chromosomes exchange genetic material Reciprocal Reciprocal translocations arise from two different mechanisms mechanisms In simple translocations the transfer of genetic material occurs in only one direction material These are also called unbalanced translocations These unbalanced Balanced Translocations and Balanced Gamete Production Gamete Individuals carrying balanced translocations have a Individuals greater risk of producing gametes with unbalanced combinations of chromosomes combinations During meiosis I, homologous chromosomes synapse During with each other with Meiotic segregation can occur in one of three ways 1. Alternate segregation Chromosomes on opposite sides of the Chromosomes translocation cross segregate into the same cell translocation Leads to balanced gametes 2. Adjacent-1 segregation Adjacent non-homologous chromosomes segregate into the same Adjacent cell cell Leads to unbalanced gametes Both c...
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This document was uploaded on 03/05/2014 for the course CELL 2050 at Tulane.

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