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Notes taken during lecture

Human Biology
Course Code
Stephen Wright

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LECTURE 05 January 25
Go beyond Mendelian inheritance to some degree
Know these terms on Extensions to Mendels laws slide
For exam!!!
No reaction to Mendels paper silence
Obscure journal in which Mendel published
Too mathematics-heavy for the time
Immediately applicable to peas and the particular crosses he focused on 3:1
ratio apply to other organisms?
Even with peas, results did not fit perfectly always
Not everything fits with Mendels proposed 3:1 ratio
….so, perhaps understandable that Mendel was ignored
o3:1 sometimes achieved
1 camp Mendel are not universally applicable
Return to blending inheritance idea
VERSUS another camp
Championed by Bateson
Advocated that Mendel discovered something key, fundamental
Different ratios in progeny then these ratios can be explained and STILL apply
Mendels law of independent assortment and equal segregation
Mendels results
oDominance and recessiveness
oGenotype is where Mendels laws will ALWAYS apply
oWhat changes is the relationship between genotype and phenotype
oMendels laws are applying in general, universally
oDominance and recessiveness may be particular to the traits in question
Inbred red line with inbred white line
oF1 was pink
oSeemingly proving blending inheritance
oF2 had ¼ red, ½ pink, and ¼ white exactly the proportions expected
under Mendels genotype ratios
oMendels laws are applying perfectly
oHeterozygote has new phenotype pink
oNotation notes: incomplete dominant (not clear which is dominant) RW
for heterozygote
oMutation leading to high level of bad cholesterol
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