from The Open University
Alternatively you can skip the navigation by pressing 'Enter'.
The Great British Year: WinterMonday, 5th October 2015 21:00 - BBC FourA frozen nation, but not a wasteland... Read more: The Great British Year: Winter
Canals: The Making of a Nation: HeritageTuesday, 6th October 2015 20:00 - BBC Four
The world’s busiest railway 2015 – Mumbai Railway: Episode 4Wednesday, 7th October 2015 00:45 - BBC Two
Canals: The Making of a Nation: HeritageWednesday, 7th October 2015 00:55 - BBC Four
The Bottom Line: Autumn 2015: Art and the Business of TasteAvailable for over a yearHow do you value something like a painting? What makes one artist worth more than another? Who decides what is in... Read more: The Bottom Line: Autumn 2015: Art and the Business of Taste
The world’s busiest railway 2015 – Mumbai Railway: Episode 4Available until Friday, 6th November 2015 01:15
BBC Inside Science: Preserving global diversity: Kew specialAvailable for over a year
Countdown To Life: The Extraordinary Making Of You: The Final PushAvailable until Saturday, 31st October 2015 00:15
Doping in rugby union: a case of papering over the cracks?Gavin Williams discusses the issue of doping and statistics on usage of performance-enhancing... Read more: Doping in rugby union: a case of papering over the cracks?
OpenLearn Live: 5th October 2015Starting a week exploring the people and places of the smallest county - then more free learning... Read more: OpenLearn Live: 5th October 2015
Beginners' ChineseLearn about Mandarin Chinese as a tool for communication and gain insights into Chinese society... Try: Beginners' Chinese now
English: skills for learningThis course is for anybody who is thinking of studying for a university degree and would like to... Try: English: skills for learning now
Meiosis and mitosis
This Unit looks at how units if inheritance are transmitted from one generation to the...
This Unit looks at how units if inheritance are transmitted from one generation to the next. First you will look at what happens to the chromosones of animals and plants during the process of sexual reproduciton. Then you will examine how genes are transmitted in particular patterns from generation to generation. These two approaches combine to illustrate how the patterns of inheritance can be explained by the behaviour of chromosomes during sexual reproduction.
After studying this unit you should know:
- the number of chromosomes is characteristic of each species and can vary enormously between species
- genetics is based on the concept of the gene as the unit of inheritance
- that sexual reproduction always includes two distinctive processes: the production of gametes, which involves meiosis, and fertilisation. The two processes are accompanied by changes in the chromosome number, from diploid to haploid and from haploid to diploid, respectively
- a particular phenotypic character is determined by the two copies of a gene that an organism possesses and these two copies are identical in a pure-breeding variety
- when organisms with contrasting characters for which they are pure-breeding are crossed, the dominant character appears in the first offspring or first filial generation and the recessive character is masked
- the genotypic ratios of a cross result from the separation of the two copies of a gene to different gametes in equal numbers, and because gametes combine at random at fertilisation. The expected ratios in genetics do not tell us the actual ratios observed, but rather the most probable ratios
- the behaviour of chromosomes at meiosis explains the segregation of the two copies of a gene and the independent assortment of genes. The linkage of genes on a chromosome can be broken by means of crossing over
- recombination – the production of new combinations of alleles – arises during meiosis from independent assortment of chromosomes and crossing over between homologous chromosomes
- the amount of crossing over between linked genes differs according to their distance apart.
- Current section: Introduction
- Learning outcomes
- 1 Unit introduction
- 1.1 Meiosis and the life cycle
- 1.2 Like begets like
- 1.3 Patterns of inheritance
- 5 Why not an exact 3:1 ratio?
- 6 Inheritance of more than one pair of contrasting characters
- 1.6 Summary
Study this free course
Enrol to access the full course, get recognition for the skills you learn and track your progress. Make your learning visible!
Meiosis and mitosis
This unit looks at how units if inheritance are transmitted from one generation to the next. First you will look at what happens to the chromosomes of animals and plants during the process of sexual reproduction. Then you will examine how genes are transmitted in particular patterns from generation to generation. These two approaches combine to illustrate how the patterns of inheritance can be explained by the behaviour of chromosomes during sexual reproduction.
This unit is from our archive and is an adapted extract from Discovering science (S103) which is no longer taught by The Open University. If you want to study formally with us, you may wish to explore other courses we offer in.
This is an extract from an Open University course which is no longer available to new students. If you found this interesting you could explore more free Biology courses or view the range of currently available OU Biology courses.
Copyright & revisions
Originally published: Thursday, 21st July 2011
- Creative-Commons: The Open University is proud to release this free course under a Creative Commons licence. However, any third-party materials featured within it are used with permission and are not ours to give away. These materials are not subject to the Creative Commons licence. See terms and conditions. Full details can be found in the Acknowledgements section.
- This site has Copy Reuse Tracking enabled - see our FAQs for more information.
If you enjoyed this, why not follow a feed to find out when we have new things like it? Choose an RSS feed from the list below. (Don't know what to do with RSS feeds?)
Remember, you can also make your own, personal feed by combining tags from around OpenLearn.