|The study of inheritance is called 1)__________________. Gregor Mendel, an Austrian monk was considered the father of genetics because of his work with garden peas. He noticed that his pea plants had seven characteristics, or 2)______________, that included seed shape, seed color, and plant height. These contrasting traits are also known as 3)___________________. Mendel observed that tall plants only produced tall plants because they were 4)_______________________________ plants. He crossed talls (TT) with short plants (tt) and got all tall plants (Tt) that he called 5)_____________ because they were a combination of tall and short peas. Then Mendel let his hybrids self-pollinate. To his surprise he got a 3 Tall to 1 Short ratio. In a moment of brilliance, Mendel said, "I believe a trait for a plant is decided by two 6)_____________ that separate during 7)___________________ (sperm and egg) formation." This statement is his law of 8)______________________. He was the first man to say that traits were determined by two genes and is now called the "FATHER OF GENETICS."|
|The combination of genes an individual has is its 9)__________________. For instance, I have the alleles "bb" for my eye color genes. My genotype is 10)_____________________ recessive. My 11)_____________________ is blue eyes. My brother had a 12)______________________ genotype of "Bb". My mother had a phenotype of blue eyes and my father's phenotype was brown eyes. If you used a device called a 13)________________ ________________ you would see that the expected genotypic ratio for a Bb x bb is 0:2:2 and the phenotypic ratio is 2:2. My parents had three children. My sister and I had blue eyes and my brother had brown.|
dominant and recessive
So far, we have studied four types of inheritance that we are seeing in our 31 facial characteristics. Men are XY and eggs are XX . The type of inheritance that is determined by whether a sperm has an "X" or a "Y" is 14)______________ inheritance. When the expression of one trait masks (or covers up) another trait and you have only two phenotypes, this is 15)___________________________________ inheritance. An example of this inheritance is ear attachment. Either ears are lobed (free) or attached. Free ears are dominant over attached.
If two contrasting traits have an in between expression (three phenotypes) it is 16)_____________________________________, such as when a long-nosed person marries a short-nosed person and produces a medium-nosed baby. Hair color is a 17)_______________________ trait because there are MANY expressions of hair color that are determined by MANY different genes.