What is the Difference Between Maternal and Paternal Chromosomes

The main difference between maternal and paternal chromosomes is that a sex chromosome with maternal origin can only be an X chromosome while a sex chromosome with paternal origin can be either an X chromosome or Y chromosome. Therefore, maternal chromosomes are called homogametic chromosomes while paternal chromosomes are called heterogametic chromosomes.

Maternal and paternal chromosomes are the two types of chromosomes found in the nucleus of the zygote produced after the fusion of gametes. Each set of chromosomes with different origins consists of 23 chromosomes (in humans), making up a nucleus with 46 chromosomes in it.

Key Areas Covered

1. What are Maternal Chromosomes
     – Definition, Origin, Sex Chromosomes
2. What are Paternal Chromosomes
     – Definition, Origin, Sex Chromosomes
3. What are the Similarities Between Maternal and Paternal Chromosomes
     – Outline of Common Features
4. What is the Difference Between Maternal and Paternal Chromosomes
     – Comparison of Key Differences

Key Terms

Maternal Chromosomes, Paternal Chromosomes, Sex Determination, X Chromosome, Y Chromosome

What are Maternal Chromosomes

Maternal chromosomes are the chromosomes in the nucleus with a maternal origin. This means these chromosomes come through the female gamete during fertilization. In humans, the set of the maternal chromosomes contain 22 autosomal chromosomes and a single sex chromosome. Here, the sex chromosome is always an X chromosome. It is due to the presence of two X chromosomes in females, determining their sex.

Figure 1: Human Chromosomes

What are Paternal Chromosomes

Paternal chromosomes are the chromosomes in the nucleus with paternal origin. It means; these chromosomes come through the male gamete during fertilization. Same as the maternal chromosomes, the set of paternal chromosomes in humans contains 22 autosomal chromosomes. Here, each paternal chromosome has a homologous chromosome in the maternal chromosome set.

Figure 2: Human Y Chromosome

In addition to autosomal chromosomes, both types of sex chromosomes, the X chromosome or the Y chromosome, can occur as the sex chromosomes in the paternal chromosome set. Consequently, the type of sex chromosome in the paternal chromosome set determines the sex of the new individual.

Similarities Between Maternal and Paternal Chromosomes

• Maternal and paternal chromosomes are the two types of chromosomes inside the nucleus.
• Each type of chromosome set contains 23 chromosomes.
• Also, each chromosome set is made up of 22 autosomal chromosomes and one sex chromosome.
• A particular autosomal chromosome with maternal origin is homologous with another autosomal chromosome with paternal origin. Sex chromosomes can be homologous in the XX situation and heterozygous in XY situation.
• Furthermore, both chromosome sets can contain X chromosomes.

Difference Between Maternal and Paternal Chromosomes

Definition

Maternal chromosomes refer to the set of chromosomes that comes from the female gametes while paternal chromosomes refer to the set of chromosomes that comes from the male gametes. Thus, this is the basic difference between maternal and paternal chromosomes.

Origin

Maternal chromosomes originate from the mother while the paternal chromosomes originate from the father.

Type of Sex Chromosomes

Type of sex chromosomes they possess is a main difference between maternal and paternal chromosomes. Maternal sex chromosome is always an X chromosome while paternal sex chromosome can be either an X or Y chromosome.

Homogametic/Heterogametic

Another difference between maternal and paternal chromosomes is that maternal chromosomes are homogametic while paternal chromosomes are heterogametic.

Conclusion

Maternal chromosomes are the set of chromosomes in the nucleus with a maternal origin. For instance, paternal chromosomes are the second set of chromosomes in the nucleus with the paternal origin. Maternal chromosomes are homogametic chromosomes since each female gamete contains X chromosomes as the sex chromosomes. On the other hand, male gametes either contain X or Y chromosome as the sex chromosome. Therefore, the main difference between maternal and paternal chromosomes is the type of sex chromosomes present in the chromosome set.

Reference:

1. Bailey, Regina. “What Are Homologous Chromosomes?” Thoughtco., Available Here
2. Miko, Ilona. “Sex Chromosomes and Sex Determination.” Nature News, Nature Publishing Group, Available Here

Image Courtesy:

1. “Karyotype” ByCan H. (CC BY 2.0) via Flickr
2. “Human chromosome Y – 400 550 850 bphs” By National Center for Biotechnology Information, U.S. National Library of Medicine – Ideograms are by NCBI’s Genome Decoration Page. (Public Domain) via Commons Wikimedia