Review of Modes of Genetic Inheritance

Genetics is the study of the inheritance and variation of traits in different organisms. Different modes of genetic inheritance are used to explain how these traits are passed on from parents to their offspring. This article will review the various modes of genetic inheritance, including autosomal, sex-linked, and mitochondrial inheritance.

Autosomal Inheritance

Autosomal inheritance is the most common form of inheritance. It involves genetic traits that are located on the autosomes, which are the chromosomes that are not the sex chromosomes. Autosomal inheritance is responsible for the majority of genetic traits, including physical characteristics, such as eye color, and many diseases, such as cystic fibrosis.

Autosomal inheritance is a type of Mendelian inheritance, which is a type of inheritance named after the scientist Gregor Mendel, who first described the patterns of inheritance in peas. Mendelian inheritance is based on the principle of segregation, which states that two copies of each gene, one from each parent, are segregated during the formation of gametes (sperm and eggs). The gametes then pass on one of the gene copies to the offspring and the other is discarded. This type of inheritance is also referred to as dominant-recessive inheritance, because some gene variants will be expressed, or dominant, while others will be hidden, or recessive.

Sex-Linked Inheritance

Sex-linked inheritance involves genetic traits that are located on the sex chromosomes, which are the X and Y chromosomes. This type of inheritance is responsible for many genetic traits, such as male pattern baldness and color blindness.

Sex-linked inheritance is based on the principle of non-disjunction, which states that during the formation of gametes, the sex chromosomes may not separate properly, leading to gametes with an abnormal number of sex chromosomes. This can lead to the offspring having an extra copy of a sex chromosome, or an extra copy of a gene located on the sex chromosome.

For example, if a male has an extra copy of the gene for color blindness, located on the X chromosome, then he will be color blind. However, if a female has an extra copy of the gene for color blindness, she will not be color blind, since she has two X chromosomes, and the normal copy of the gene will compensate for the extra copy.

Mitochondrial Inheritance

Mitochondrial inheritance is the inheritance of genetic traits located on the mitochondrial DNA. Mitochondrial DNA is passed down from the mother to all of her offspring, and is responsible for certain genetic traits, such as mitochondrial diseases.

Mitochondrial inheritance is based on the principle of maternal-effect inheritance, which states that the mitochondrial DNA will be passed down from the mother to all of her offspring, regardless of the father's genes. This means that some genetic traits, such as mitochondrial diseases, will be passed down from the mother to all of her offspring.

Conclusion

In conclusion, there are three main types of genetic inheritance: autosomal, sex-linked, and mitochondrial inheritance. Autosomal inheritance involves genetic traits located on the autosomes, and is based on the principle of segregation. Sex-linked inheritance involves genetic traits located on the sex chromosomes, and is based on the principle of non-disjunction. mitochondrial inheritance involves genetic traits located on the mitochondrial DNA, and is based on the principle of maternal-effect inheritance. Each type of inheritance is responsible for different genetic traits and diseases.