SCIENCE-9-Non-Mendelian Inheritance.pptx

Non-Mendelian

1. Non-Mendelian Inheritance

2. 3.Allele – alternative form of gene - is one of two or more versions of DNA sequence (a single base or a segment of bases) at a given genomic location. 1.Genotype - genetic makeup of an organism; in other words, it describes an organism's complete set of genes. 4.Phenotype – observable traits of an organism (brown, tall, short) 2.Homozygous – gene combination having the same/identical alleles for a single trait (HH) Heterozygous – gene combination having two different alleles ( Hh )

3. 5.Dominant Traits - the traits which are expressed more often and observed more commonly in the population is called dominant trait 8.Recessive Traits - can be carried in a person's  genes  without appearing in that person. For example, a dark-haired person may have one gene for dark hair, which is a  dominant trait  , and one gene for light hair, which is recessive.

4. Non-Mendelian Inheritance 6. Incomplete Dominance is when the homozygous dominant trait is crossed with a recessive trait, the result would be the expression of a trait that is in between the dominant and recessive traits. 10.in incomplete dominance, as the name implies, the offspring does not completely express the dominant trait when the parent with the homozygous dominant trait and parent with the recessive trait are crossed . Ex. (R) Red Snapdragon + (r) White Snapdragon = Pink Snapdragon 100%pink

5. 7.Codominance - is when the two different traits are both present in an individual. This means that a heterozygous genotype in codominance will express both traits . -Ex. (B)Black Chicken + (b)White Chicken = Checkered/Black and White Colored Chicken(Bb) -Ex. Blood type AB is codominance .

6. 9.Sex-Linked Inheritance - characteristics (or traits) that are influenced by genes carried on the sex chromosomes. In humans, the term often refers to traits or disorders influenced by genes on the X chromosome, as it contains many more genes than the smaller Y chromosome . -Color blindness is an example of an X-linked recessive trait. As the name implies, X-linked traits are traits that are linked to the X chromosome. -There are 23 pairs of chromosomes or 46 chromosomes in humans. -The first 22 pairs are termed as autosomes. -The 23 rd pair is either XX or XY chromosomes.

7. Multiple Alleles - a gene can have more than two allelic forms segregating within a  population. These genes are referred to as having multiple alleles. - This does not mean that the gene in a particular individual possesses more than two alleles. An individual can only have a maximum of two of the alleles, one maternal and one paternal, no matter how many alleles exist in the population . - An example of multiple alleles is blood type. There are three alleles for the ABO human blood type: A, B, and O.