Bio 101 - Genetics and Reproduction

Genetics and Reproduction

Jackie Johnson

BIO/101

10/02/2017

David Ormond

Genetics and Reproduction

Asexual Reproduction: this type of reproduction is common among invertebrates- that is animals without backbones. Asexual reproduction is a type of reproduction is a type of reproduction by which offspring arise from a single organism, and inherit the genes of that parent only; it does not involve that fusion of gametes, and almost never changes the number of chromosomes. Asexual reproduction is the primary form of reproduction for single cell organism.

The current hypotheses suggest that asexual reproduction may have benefits when rapid population growth is important or in stable environment. While sexual reproduction offers a net advantage by allowing more rapid generation of genetic diversity allowing adaptation to changing environment.

Some species alternate between asexual and sexual reproduction, this is an ability known as heterogamy, depending on conditions. Alternation is observed in several rotifer species and a few types of insects, such as aphids which will under certain conditions, produce eggs that have not gone through meiosis, thus cloning themselves.

But in long term lack of sexual reproduction compromises their ability to adapt to environment because they do not benefit from the genetic variation introduced by sexual reproduction.  Although asexual births have been observed in vertebrate in captivity, scientists have not yet seen it happen in the wild.

Evolutionary and population geneticist Warren Booth at N.C State University Raleigh and his colleague Gordon Schutt investigated a female copperhead at the N.C aquarium at Fort Fisher. Over the past 5 years, she had only encounter 1 male snake- a corn snake- and interbreeding between 2 species is considered unlikely or impossible. In 2009, this copperhead gave birth to a litter of four offspring that were outwardly normal in appearance, two of which were alive at birth. Analysis of DNA from the mother, one of the live offspring, and one of the still born progeny revealed no signs of genes from a father, suggesting a true virgin birth.