HumanInheritance160-page9

HumanInheritance160-page9 - Hybrid Corn on Right...

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Human Inheritance Patterns - 9 Other Chromosome Differences - Polyploidy Polyploidy is the increase in the number of sets of chromosomes, usually resulting from the formation of diploid gametes. Polyploidy occurs naturally in many plants and may produce larger, hardier individuals. If a diploid gamete unites with a normal haploid gamete, the triploid hybrid is sterile (no homologous matches at meiosis). If both gametes are diploid, the tetraploid individuals are often fertile. Polyploidy is used extensively in developing agricultural varieties. Polyploidy occurs naturally in many plants and may produce larger, hardier individuals. Plants we consume are often hybrid varieties selected for their enhanced productivity. Wheat grown today is a polyploid composite of several ancestral species. A naturally occurring tetraploid rat is found in Argentina.
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Unformatted text preview: Hybrid Corn on Right Tympanoctomys barrerae , 4n Rat Extra-nuclear gene expression And for our final note on transmission of characteristics from generation to generation, Mendelian inheritance addresses the behavior of genes on chromosomes. Organelles, such as mitochondria and chloroplasts (and all plastids) have small circular pieces of DNA, and that DNA is transcribed and translated within the organelle. Mitochondria and chloroplasts are self-replicating. In sexual reproduction, only the egg cell's cytoplasm is passed to the zygote, so only maternal mitochondrial and chloroplast DNA will be transmitted from generation to generation. Some genetic disorders are traced to mutations in mitochondrial DNA that codes for proteins in the electron transport chain. Mutations in mitochondrial DNA may be one reason cells age....
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This note was uploaded on 12/29/2011 for the course BIO 151 taught by Professor Edwards during the Spring '10 term at SUNY Stony Brook.

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