Transcript Sexual Exploits in experimental evolution

WHY DO IT?
ADVANTAGES OF SEX
DISADVANTAGES OF SEX
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GREATER GENETIC VARIABILITY
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ONLY CONTRIBUTE HALF OF GENETIC MATERIAL
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DNA REPAIR MECHANISMS INVOLVED WITH
RECOMBINATION
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ONLY HALF OF THE POPULATION CAN BEAR OFFSPRING
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MAY SPEED THE RATE OF ADAPTATION THROUGH
NATURAL SELECTION
HAVE TO FIND A SUITABLE MATE, IN DOING SO MAY
ALARM PREDATORS
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CARE OF YOUNG TENDS TO FALL MORE HEAVILY ON
ONE MEMBER OF THE SEXES, CREATING A HIGHER
ENERGETIC COST ASSOCIATED WITH THAT GENDER
HOW TO TEST WHICH IS BETTER?
VIRUSES
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VIRUSES HAVE SEX VIA SEGMENT REASSORTMENT
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VIRUSES EXCHANGE GENETIC MATERIAL WHEN 2 OR MORE VIRAL CELLS INFECT
THE SAME HOST CELL
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THE EXPERIMENT INVOLVED RAISING THE RATIO OF VIRAL TO BACTERIA HOST SO
COINFECTION WOULD BE MORE COMMON
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EXPOSED VIRUS TO PROFLAVINE, WHICH CAUSES FRAMESHIFT MUTATIONS
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RESULTS SHOWED THAT LINEAGES THAT UNDERWENT RECOMBINATION WERE
ABLE TO ADAPT QUICKER TO THE EFFECTS OF PROFLAVINE
BACTERIA
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3 METHODS OF BACTERIA SEX: CONJUGATION, TRANSFORMATION, AND
TRANSDUCTION
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IN ORDER FOR SEXUALITY TO BE FAVORED DELETERIOUS MUTATIONS MUST
OCCUR ONCE PER GENOME PER GENERATION, AND THAT THE MUTATION HAS A
NEGATIVE EFFECT ON FITNESS
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LINES UNDERGOING RECOMBINATION EXPERIENCED GREATER FITNESS
YEAST
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DISPLAY ISOGAMOUS MATING VERSUS ANISOGAMOUS
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YEAST UNDERGO SEXUAL REPRODUCTION WHEN THEY ARE NITROGEN DEPRIVED
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YEAST CAN HAVE HOMOTHALLIC SEXUAL CYCLES AND HETEROTHALLIC SEXUAL
CYCLES
• WHICH DO YOU THINK WOULD ALLOW FOR GREATER DIVERSITY?
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REULTS WERE THAT SEXUALS HAD AN ADAPTIVE ADVANTAGE TO A HOT, SALTY
ENVIRONMENT