363 lecture 15-2008 - genetics 4

363 lecture 15-2008 - genetics 4 - The entrance to the...

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The entrance to the Global Seed Vault, on a Norwegian Island near the North Pole. This week it received its first seeds, under a project to store every type of seed from every seed collection in the world. Already, three-quarters of biodiversity in crops has been lost in the last century, according to the United Nations Food and Agriculture Organization.
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An automated digital monitoring system controls temperature and provides security akin to a missile silo. No one person has all of the codes for the entrance. The vault descends almost 500 feet into the permafrost, with the entrance tunnel designed to withstand bomb blasts and earthquakes.
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Female fur seals show active choice for males that are heterozygous and unrelated Much debate surrounds the exact rules that influence mating behaviour, and in particular the selective forces that explain the evolution of female preferences. A key example is the lek paradox, in which female choice is expected rapidly to become ineffective owing to loss of additive genetic variability for the preferred traits. Here we exploit a remarkable system in which female fur seals exert choice by moving across a crowded breeding colony to visit largely static males. We show that females move further to maximize the balance between male high multilocus heterozygosity and low relatedness. Males rarely move more than a body-length during the main part of the breeding season. Such a system shows that female choice can be important even in a strongly polygynous species, and at the same time may help to resolve the lek paradox because heterozygosity has low heritability and inbreeding avoidance means there is no single 'best' male for all females. Nature 445, 912-914 (22 February 2007)
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Females move further to find a more heterozygous (less related) partner. IR estimates the relatedness of an individual's parents using the extent of allele sharing relative to random expectations. Open circles show the mean minimum IR of males present within a radius of the distance moved.
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…..an example of what sociologists call "assortative mating," the increasing tendency of educated, affluent people to unite in marriage. Washington Post, 4 March 2007. Reading: part of chapter 11 on inbreeding CONS 670 reading: Dimond and Armstrong. 2007. Adaptive harvesting of source populations for translocation: a case study with New Zealand Robins. Conservation Biology 21(1):114-124.
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Gene flow: major points 1) High m ij homogenizes allele frequencies in two populations 2) Rate of gene flow influences N e of recipient population and metapopulation 3) A small amount of gene flow may counteract genetic drift and conserve genetic diversity in small populations
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363 lecture 15-2008 - genetics 4 - The entrance to the...

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