Dwarfism in humans is a dominant trait. Therefore, an individual who is dwarf will be homozygous.

When a person dies due to an allele combination than it is called as lethal allele combination.

To form identical twins, one fertilised egg (ovum) splits and develops two babies with exactly the same genetic information. This differs from fraternal twins, where two eggs (ova) are fertilised by two sperm and produce two genetically unique children, who are no more alike than individual siblings born at different times.

Short repeat sequences are present in the protein coding sequences in DNA.

Sometime in the 18th or 19th century, a woman who carried the allele responsible for Huntington’s moved to the area and had 10 children. Many of the current residents of Lake Maracaibo region of Venezuela are descended from her. This is an example of bottleneck effect.

Environmental factors most affect the expression of __________.

Characteristics shared by adopted children and their biological parents are mostly ____ while their similarities with adoptive parents reflect ____ influences.

Recessive illness causing alleles persist in heterozygotes in a population.

Bottlenecks are detrimental to the viability of a species because of the loss of genetic diversity and the potential risk for inbreeding and the expression of recessive genetic traits.

Bonus: The breeds of dogs is an example of artificial selection.