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a. __create different versions of genes known as __
i. Once differences arise, __of __during __ produces variation that results in each mumber of a sexually reproducing population having a unique combo of traits
- Mutations
- alleles
- reshuffling
- alleles
- sexual reproduction
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a. Sexually Reproducing organisms
i. Behavior of chromosomes during __ and __ is responsible for most variation
1. __ (one type)
a. Random orientation of pairs of homologous chromosomes at __ produces genetic variation
i. Metaphase I: pairs (one maternal and one paternal chromosome) are on __
1. Orientation toward poles is __
a. Due to independent positioning at __, first meiotic division results results in sorting of __ i. Independent assortment
ii. Each daughter cell is one outcome of possible combos
b. To determine number of possible arrangements: __ (humans __)= 8.4 million
- meiosis and fertilization
- Independent assortment of chromosomes
- metaphase I
- metaphase plate
- random
- metaphase I
- maternal and paternal homologs into daughter cells
- 2n
- 223
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1. Crossing Over
a. Produces __chromosmomes, individual chromosomes htat carry genes derived from two different parents
i. In meiosis in humans, an average of __ to __ events occurs per chromosome pair, depending on __of chromosomes and __
- recombinant
- one to three crossover
- size
- position of centromeres
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Crossing over begins in __ as __ pair loosely along their lengths
i. Each gene aligned with corresponding gene on other homolog
1. DNA of two __—one maternal and one paternal—is broken by specific proteins at corresponding points, and the two segments beyond the __ are each joined to the other chromatid
- prophase I
- homologs
- nonsister chromatids
- crossover point
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Crossing over in Metaphase II
a. Metaphase II
i. Chromosomes contain one or more __chromatids and can be oriented in two alternative, nonequivalent ways with respect to other chromosomes, because sister chromatids no longer __
b. __
i. Different possible arrangements increases number of genetic types
- recombinant
- identical
- Meiosis II
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1. __
a. 223 (8.4 million) possible combinations
i. Fusion of gametes during fertilization will produce zygote with any of about __ (223 x 223)
- Random Fertilization
- 70 trillion
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