Many characteristics of domestic plants and animals are passed from parent to offspring. The first clear explanation of patterns of inheritance was provided by an Australian Monk, in 1865. After 10 years of research, Mendel put forward two principles of inheritance:
- various hereditary characteristics were controlled by factors (genes) and that these occurred in pairs.
- during the formation of gametes, the pairs of factors separate. Each gamete only receives one set of factors (genes), the other set going to another gamete.
- various hereditary characteristics were controlled by factors (genes) and that these occurred in pairs.
- during the formation of gametes, the pairs of factors separate. Each gamete only receives one set of factors (genes), the other set going to another gamete.
Mendel's Discoveries:
Mendel did work with plants but his discoveries apply equally well to animals also. Gregor conducted breeding experiments with the edible garden pea plant. Mendel was fascinated by the number of traits expressed in contrasting forms with this particular plant. This is when Mendel began to study seven pairs of contrasting characteristics which the alternatives were easily identifiable .
After this, Mendel began another experiment. This time he made sure his plants were pure breeding for the characteristic he wanted to pay attention to. Plants pure breeding for yellow seeds were crossed with plants pure breeding for green seeds. He later found that the offspring (progeny) resembled only one of the parents. The offspring were all plants that produced yellow seeds. These offspring are known as hybirds because they have all genetic information. Mendel referred to the characteristic shown by the hybrid as the dominant trait because it masked the appearance of the other characteristic, which he called the recessive trait.
The second generation of plants showed an appearance of 3:1 ratio. This meant that for every three dominant trait with one recessive trait.
The results from many experiments conducted over several years of study concluded Mendel's theories. He stated that hereditary factors (genes), were unchanged as they passed from one generation to the next. Also he created the principle of segregation- in the formation of gametes, each only receives one factor(gene) for each trait.
After this, Mendel began another experiment. This time he made sure his plants were pure breeding for the characteristic he wanted to pay attention to. Plants pure breeding for yellow seeds were crossed with plants pure breeding for green seeds. He later found that the offspring (progeny) resembled only one of the parents. The offspring were all plants that produced yellow seeds. These offspring are known as hybirds because they have all genetic information. Mendel referred to the characteristic shown by the hybrid as the dominant trait because it masked the appearance of the other characteristic, which he called the recessive trait.
The second generation of plants showed an appearance of 3:1 ratio. This meant that for every three dominant trait with one recessive trait.
The results from many experiments conducted over several years of study concluded Mendel's theories. He stated that hereditary factors (genes), were unchanged as they passed from one generation to the next. Also he created the principle of segregation- in the formation of gametes, each only receives one factor(gene) for each trait.