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HPsych-Chapter2:Gene
Question | Answer |
---|---|
number of chromosomes in humans | 23 |
percent related to either parent or any sibling | 50% |
homozygote dominant/recessive cross results | all heterozygotes |
heterozygote and homozygote recessive cross results | 1/2 homozygote recessive, 1/2 heterozygote |
two heterozygotes cross | 1/2 heterozygotes, 1/4 homozygous recessive, 1/4 homozygous dominant |
components of gene transmission | dominant and recessive and any complications to simple dominance |
complications to simple dominance | multiple gene effects, sex linkage, codominance, parental coding, crossing over, and x-deactivation |
example of multiple gene effects | partial albino gene at a different chromosome affects hamster coat color (if recessive, they get a normal color. if not, albino trumps the color coded on the other chromosome) |
examples of sex linkage | hemophilia (skips a generation when manifesting), color blindness-- usually affects males more frequently |
codominance | two dominant genes can produce their effects together (Ex. the ABO blood typing system-- A and B are both dominant) |
parental coding | gene expression is affected by which parent you got it from |
crossing over | homologous pairs exchange parts of chromosomes to create new genetic combinations |
x-deactivation | one X chromosome turns off in different cells during development of females to rectify the unbalance between males (XY) and females (XX) (Ex. calico cats) |