BI SC 002 Lecture Notes - Lecture 8: Mendelian Inheritance, Parasitic Disease, Hemoglobin
19 Sep 2016
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Document Summary
When chromosomes fail to separate fully, this is an error called non- disjunction. Can happen at anaphase i or anaphase ii. Result is an egg or sperm cell with a missing chromosome, or multiple copies of a particular chromosome. If this gamete fuses with another at fertilization, the zygote will have an odd number of chromosomes. In most cases, disease is not caused by genes alone. Environmental factors can cause disease: smoking increases chance of lung cancer, diet and lifestyle alter the likelihood of contacting diabetes. Microbial infections can cause disease: cold and flu viruses, malaria parasite. Often found as a combination of different factors: inherited/genetic, environmental, microbial infections. Some human traits follow mendelian inheritance patterns. Single genes on autosomes or sex chromosomes govern > 6000 genetic abnormalities. Single gene disorders affect about 1/200 people. 50% chance of any offspring inheriting the condition. Possession of one dominant allele results in a phenotype.
