Causes of apomixis, Biology

Assignment Help:

Causes of Apomixis

Apomictic species are generally hybrids or polyploids, as a consequence, there is irregular meiosis. Apomixis appears to be controlled by a set of genes. The trait is genetically inherited. The genes controlling sexual reproduction are non-allelic to those of apomixis. Accordingly, any line of dissent carrying the genes for apomixis will produce both types, apomicts as well as sexually reproducing plants. It has been proposed that apomixis is governed by recessive genes. The three genes (AABBCC) determine the breeding behavior.

In homozygous condition a forms unreduced eggs, b prevents fertilization, and c promotes egg development without fertilization. Thus, aaBBCC will have unreduced egg but cannot develop without fertilization, AAbbCC produces reduced egg but no embryo development take place because fertilization is prevented, and AABBcc will show normal sexual behaviour because the gene C has no effect in the presence of A and B. As a consequence of apomixis, genetic variability in such species is frozen as they have the same genotypes as parents. However, facultative apomicts have an advantage as they have retained both kinds of reproduction.


Related Discussions:- Causes of apomixis

Partial pericardiectomy-pericardial effusion, Partial Pericardiectomy :  ...

Partial Pericardiectomy :  The approach can be either by a left anterolateral thoracotomy or median sternotomy. For pyogenic pericarditis with adhesions and loculations a par

What are fossils, What are fossils? The Fossils are petrified vestiges ...

What are fossils? The Fossils are petrified vestiges of beings that lived in the past conserved by chemical and geological processes and found within rocks and sedimentary stra

PHYLUM MOLLUSCA, How we attempt a question of phylum mollusca?

How we attempt a question of phylum mollusca?

Explain what is dna, Explain what is DNA? DNA : DNA is the source of t...

Explain what is DNA? DNA : DNA is the source of the information that directs the development of the cell. Although all segments of DNA are not active in every cell in the huma

Comparing the dna of a calfs liver and thymus, When comparing the DNA of a ...

When comparing the DNA of a calfs liver and thymus, which would be predicted to have more DNA and why? What are the differences of the DNA between the two?

Primary succession - community change, Primary Succession - Community Chang...

Primary Succession - Community Change In primary succession on a terrestrial site the new site is first colonised by a few hardy pioneer species that are often microbes, liche

Show the ploidy of life cycles, Q. For each of the three kinds of life cycl...

Q. For each of the three kinds of life cycles what is the respective ploidy of the individual that represents the adult or lasting form? In the haplontic haplobiontic life cycl

What are primary consumers, What are primary consumers? Can a food chain pr...

What are primary consumers? Can a food chain present quaternary consumers without having secondary or tertiary consumers? Can a tertiary consumer of one chain be a primary or secon

Difference between open system and closed system, DIFFERENCE BETWEEN OPEN S...

DIFFERENCE BETWEEN OPEN SYSTEM AND CLOSED SYSTEM - S .No. C h arac t er O p en system C losed system

How do plants solve the problem of transporting substances, How do plants s...

How do plants solve the problem of transporting substances throughout their tissues? In bryophytes the substance transport is completed by diffusion. In tracheophytes (pteridop

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd