Gregor Mendel ~ Father of Genetics Mini Biography Video

Gregor Mendel Discovered the basic principles of heredity Worked with pea plants Studied 7 different traits Gregor Mendel

Mendel’s Peas Self-pollination - using sperm & egg of the SAME plant Results in offspring IDENTICAL to the parent

Mendel’s Peas Cross-pollination – using sperm & egg from two DIFFERENT plants Results in offspring with traits from BOTH parents

Mendel’s Observations Crossed pure breeding yellow (yy) pod plants with pure breeding and green (YY) pod plants To his surprise, ALL the offspring had green (Yy) pods!!!

Mendel’s Observations Crossed heterozygous green (Yy) with heterozygous green (Yy). Result= 3 green pods : 1 yellow pod

How did the yellow pod reappear?? Say WhaT??

Mendel’s Conclusions Two conclusions: Individuals carry two alleles for each trait, but pass down only one allele to offspring One allele is dominant over the other.

Mendel’s Conclusions When present dominant alleles will always be expressed Recessive alleles will only be expressed if there are 2 present EX: Tall dominant over short EX: Yellow seeds dominant over green seeds

Segregation of Alleles During Meiosis Reappearance of recessive allele showed that the parent’s alleles must separate allowing only them to pass on only one allele. Each gamete carries one allele for each gene Ex. Either tall (T) or short (t)

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