Gregor Mendel is the "Father of Genetics". He is an Austrian Monk who is the first known person to perform experimentation on genetics and heredity. Mendel attended the garden at the monastery where he lived. He predicted that in each different colored flower, pea plants would bloom. It made him wonder how that could even possibly happen.
Genetics is the study of heredity. Heredity is the passing of traits from a parent generation to the offspring generation. All traits are passed on units called genes. Genes are units of heredity found in DNA, and it contains genetic material.
Every gene is composed of two alleles. Alleles are the sub-unit of heredity. One allele comes from the mother’s DNA, and the other one comes from the father’s DNA. Two alleles make one gene.
A monohybrid cross is a process done to form a particular trait. If you wanted to breed an all black shar-pei like the one above, a dog breeder will keep breeding all black shar-pei's to confirm that the black fur gene is in the heredity.
To be dominant or recessive is inherent to a gene or allele. If a gene or allele is recessive, a dominant gene or allele will take over. If the recessive allele is present, you will not be able to see it physically. Capital letters constitute dominant alleles and lowercase letters constitute recessive alleles.
Two of the same types of alleles is called a Homozygous gene. The prefix “Homo” means the “same”. A heterozygous gene is a gene in which it has both a dominant allele and a recessive allele. (Capital letter and lowercase letter).
A genotype would be described as heterozygous or homozygous. A phenotype is the gene that you physically see.
During Mendel’s experiments in plant breeding he noticed that sometimes a trait would seem to disappear in one generation of offspring, and then reappear in another generation! That’s when “Mendel’s Principle of Dominance” was created. Mendel’s Principle of Dominance is that, recessive alleles can still be present, even if they are not displayed, and can show up in the next generation if they combine with other recessive alleles.
Punnett squares are a type of tool that is used to help determine genotypic and phenotypic probabilities in offspring. Punnett squares are also used to determine parental genotypes based on offspring phenotypes.
Many of are traits are actually controlled by multiple versions of the same gene. Gene segments activate to make a cell specialize. This is possible because of our personal epigenome. An epigenome is an “outer layer” of genetic information found in a person’s DNA. It serves as a punctuation marker, making it easier to “read” gene expression and activate or silence certain genes.
Incomplete dominance occurs when there is a blending of traits due to the presence of multiple dominant genes. This is because multiple dominant genes are present and all of them show equally. Codominance is another intermediate pattern of inheritance. Codominance is when both alleles contribute equally to the phenotype, resulting in a sharply contrasting appearance in color/ variation, etc… through the organism.
An organism's genome is located on the chromosomes, and those chromosomes come in pairs. One pair determines the sex of the organism. Those chromosomes are called sex chromosomes. They are the 23rd chromosome in humans, they determine whether a baby is male or female. (An XX combination means female, XY means male.) The rest of the chromosomes in the genome are known as autosomes. They are chromosomes that are only 1-22 in humans. They can help find out before a baby is born if it’s healthy or if it has any problems or disorders due to a birth defect,
Vocabulary terms (not included above):
Carrier- An organism that does not exhibit a genetic disorder ir disease but contains an allele which could potentially be passed along to their offspring.
Sex-linked trait- A trait that is passed specifically on the X or Y chromosome.
Karyotype- The chromosomal profile of a person.
Pedigree- A chart that assists with tracking select traits through different generations.