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Meiosis > Research Links
"Meiosis," the first chapter of Unit 3 "Gene Structure and Expression,"
discusses the changes that occur inside reproductive cells during cell
division. Meiotic division produces cells suited for sexual
recombination, which is one of the sources of genetic variation that
evolution is able to act on. The following links lead to sites and
articles that describe the cellular, genetic, and medical aspects of
meiotic division and sexual recombination.
9.1 How Does Meiosis Occur?
Meiosis and Fertilization in Ascaris
This site describes the stages in meiosis of the nematode Ascaris sp.
Several images help to show the state of cellular components during the
cell division process. Links at the bottom lead to other tutorials on
meiosis as well.
Keywords: meiosis, fertilization
Meiosis
This tutorial at the University of Arizona's Biology Project site
takes the viewer through the steps of meiosis one at a time. Follow
the links to several QuickTime animations and links to a description
of karyotyping.
Keywords: meiosis, chromosome, karyotype
9.2 The Consequences of Meiosis
Meiosis and Sexual Life Cycles
One of the side benefits of sexual reproduction and meiosis is the
introduction of genetic variation into gametes through crossover
events and other molecular changes during early meiotic stages.
This article describes how this genetic variation due to meiosis
arises.
Keywords: meiosis, crossover, genetic variation
Thomas Hunt Morgan
Thomas Hunt Morgan, as mentioned in the chapter, received the Nobel prize in 1933
for his work on chromosomes and heredity. Morgan's work described the chromosomal
basis of crossing over, laying the groundwork for much of the future work on the
changes that chromosomes undergo before sexual recombination.
Keywords: Thomas Hunt Morgan, crossover, chromosome, heredity
Incomplete Meiosis
Incomplete meiosis can produce abnormalities in chromosome numbers, which most often
has a negative effect on the gametes produced. However there are times when
mistakes in meiosis may give rise to new types of viable gametes and offspring
that cannot mate with the parent species. This article describes some of the common
mistakes in meiosis that lead to such chromosomal abnormalities in humans
Keywords: incomplete meiosis, polyploidy, trisomy, monosomy
9.3 Why Does Meiosis Exist? Why Sex?
John Maynard Smith
John Maynard Smith's work on genetics and the transmission of information sparked
scientific work on the genetics and evolution of sexual reproduction. In this
interview Smith discusses his usage of mathematical models to understand the
information processing that occurs in cellular sexual recombination.
Keywords: John Maynard Smith, genetics, sexual reproduction
Sexual Reproduction
This article discusses the purpose of sexual reproduction, relating the question
to several different areas of research, including the origin and evolution of life
on Earth. Follow the links to the panspermia site to learn about one controversial
theory on the origins of life.
Keywords: sexual reproduction, meiosis, panspermia
9.4 Mistakes in Meiosis
Polyploidy
Errors in meiosis often lead to incorrect chromosomal numbers in gametes.
This can result in polyploidy, in which an extra set of chromosomes exists in the
somatic cells of an organism. This site describes the origins and effect of
polyploidy in both plants and animals.
Keywords: polyploidy, recombination, meiosis, errors
Down Syndrome
Down syndrome, a relatively common condition resulting from meiotic abnormalities
in humans, is discussed in detail at this site. Follow the many links to learn
about the science, medicine, and social impact of this genetic disease.
Keywords: Down syndrome, genetic disease, trisomy
Birth Defects
There are many meiotic genetic abnormalities that result in viable births, as can
be seen on this Birth Defects site. Select links that relate to trisomies,
monosomies, and other genetic errors to see the effects of these genetic errors on
human health.
Keywords: birth defect, genetic disease, trisomy, monosomy
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2003
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