R
RR Rr
Rr
rr
na classic experiment using pea shape, Mendel conducted two separate genetic crosses. In the first cross the parent plants were
true breeding for pea shape, one had round peas (R and the other had wrinkled (1). The first cross produced a filial 1 generation
of allround peas. In the second cross Mendel bred plants from the filial 1 generation. This cross produced different results. Out of
Approximately 1000 plants about 75% were round and 25% were wrinkled.
From these experiments Mendel developed four hypotheses. They include all BUT
one heritable factor may be dominant and mask the other factor
any organism that shows a heritable factor must be homozygous.
an organism has two heritable factors, now called genes, one from each
parent
a sperm or egg carries only one heritable factor for each trait in the
offspring