Worksheet Extensions INDEX
CHROMOSOME CHANGES, HYBRIDS and SPECIES
REGULATOR GENES AND POLYGENIC INHERITANCE
Here are a few engaging worksheets that could be assigned for homework and/or extra credit in connection with a few of our ENSI lessons. Each one involves a short reading selection, followed by a number of questions based partly on the reading, partly on current or previous class topics, and partly on experience with a few ENSI lessons. For each blank worksheet packet, there is an identical packet containing reasonable responses to help teachers unfamiliar with the topic. This “Reasonable Responses” can be obtained from the ENSI webmaster by email from you using your school email address. Be sure to specify which worksheet you want the responses for.
These worksheets were developed and kindly offered to us by ENSI-using teacher, Tom Mueller.
This begins with a brief posting by Carl Zimmer on his blog about how anti-evolutionists criticize the scientific findings that one of our chromosomes resulted from the fusion of two shorter chromosomes found today in Chimpanzees and Gorillas. They maintain that chromosome numbers are fixed for each and every species, and just do not change (at least not as part of any differentiation between different species). Several examples are presented during discussion about the formation of animal hybrids and the chromosome changes that accompany that process.
This worksheet and its discussion would be helpful to do before doing one of these ENSI lessons:
Chromosome Fusion OR The Mystery of the Matching Marks
This deals with genetic material often found in the non-protein-coding (“Junk”) DNA, and showing various kinds of regulatory functions in the expression of other genes. These regulatory genes are variously called “enhancers,” promoters,” operators,” etc., depending on their particular functions. One of these “enhancer” genes is used to show how they affect gene expression in several areas in transgenic mouse embryos. It is suggested that the differences between humans and chimps may well be due primarily to the action of such enhancer genes rather than basic protein-producing genes.
It would be helpful if the ENSI “Cytochrome C (Molecular Biology & Phylogeny)” lesson has been done earlier. This worksheet would also work well as an introduction to the ENSI “Case of the Threespine Stickleback” lesson, which goes more deeply into regulatory genes during development.
The Strange Case of Oliver the Chimpanzee
Here’s the account of a chimpanzee that has many of the physical and behavioral traits of a human that might be due to the influence of certain regulatory genes. Some have suggested that Oliver might be another sub-species of chimps. The subject of polygenic inheritance and pleiotropy are also discussed. Since most human characteristics and disorders are influenced by non-Mendelian polygenic inheritance, the American Society of Human Genetics (ASHG) has suggested that more attention be given to polygenic inheritance, perhaps even more than classical Mendelian inheritance, in high school biology classes. This worksheet could well be an interesting segue into that topic.
This worksheet could well follow the genetics topic of multiple alleles (e.g., blood groups) and the genetics of most human traits and diseases (as well as those of other animals). Also, as an engaging extension of the previous worksheet: Human-Chimp DNA (above).