Online Lab- Genetics

Genetics is the study of inheritance, how characteristics are passed from one generation to the next (eye color, blood type, ect). A person's genes are inherited from their parents, one set of chromosomes from each parent cell. Gametes are haploid with only one of each chromosome and therefore one of each gene. When two gametes fuse at fertilization the zygote now has two of each gene (that is a pair of alleles for each gene). Where the alleles are different, one may be recessive and the other dominant. The dominant allele will determine the characteristic.




In the dragon lab (as seen on the right) we change the alleles of the bottom dragon, until its phenotype (physical characteristics) matched that of the top dragon. For example, the allele for horns is dominant on chromosome 1a and recessive on chromosome 1b, resulting in horns. These characteristics can be predicted (as far as the probability of one characteristic over another) by using a punnett square. In the square, the allele combination of one parent goes on top, and the other parent goes on the side. This can be seen in the fruitfly lab (on the right), where we discovered the probability of the offspring having long wings versus short wings. When both parents are heterozygous, the offspring have a 75% chance of having the dominant phenotype and a 25% chance of having the recessivie phenotype. Important vocabulary for the section is as follows

• Genotype- refers to the genes of an individual


• Phenotype- characteristic of the individual(long wings, short wings, no legs, horns, scales, ext. Does not necessarily have to be easily observable)


• Allele- alternative forms of a gene having the same position on a pair of chromosomes and affecting the same trait


• Cross-is the inheritance of alleles(When we crossed two heterozygous fruit flys their offspring had the poetential to inherit either Ll(long wing) or ll(short wing) alleles


• Dominant allele- is the allele that exerts it phenotypic effect in heterozygote. It will mask a recessive allele. ( In the case of the dragon, the dominant H masks the recessive h, thus givng the dragon horns)


• Recessive allele-is the allele that exerts it phenotypic effect only in the homozygote.( In the dragon lab the f allele from both chromosomes is recessive, which results in a fire breathing dragon)

Our genetic make-up makes us who we are individually, while giving us a combination of traits handed down from our parents, whose traits were handed down from their parents, ect. The basis of evolution is based off of two facts, that DNA determines the nature of an organism, and also that there are mechanisms that DNA can be modified by. Since DNA makes the organism, and this DNA can be changed, the theory is that if successive changes are passed down to successive offspring, changes in the genetic code could occur over a period of time. In this way, genetics and how they are inherited are very important in todays research.

Works Cited

Genetics and Evolution http://atheism.about.com/library/FAQs/evolution/blfaq_evolution_evidence03.htm