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How Am I Related to my Mother?. Adapted from: EPID 513- 2005 Ashley Larry Samia. We often have a sense that we are related to our mother in some way…. “A chip off the old block!”. Appearance. Abilities and talents. “Like mother, like daughter.”. Similar behavior and personality.
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How Am I Related to my Mother? Adapted from: EPID 513- 2005 Ashley Larry Samia
We often have a sense that we are related to our mother in some way… “A chip off the old block!” Appearance Abilities and talents “Like mother, like daughter.” Similar behavior and personality High blood pressure runs in the family… “Sharing the same blood” “She’s got her mother’s eyes.”
Learning Objectives • Understand that half of our genes come from our mothers. • Understand why we are not exactly like mom – or even half of her. • Learn what genetic testing can and can’t tell you about your relationship with your mom. Photo courtesy of http://www.mercola.com/2003/jun/21/genes.htm
The Passing of Genes: key concepts • The passing of genes from parent to child is the basis of inheritance. • Traits are physical or behavioral characteristics such as height, eye color, hair texture, personality, talents, skills, inheritance of diseases. We receive traits in the form of genes from our mother and father. • Each individual has two complete sets of 23 chromosomes. Chromosomes are composed of DNA that contains two copies of genes for each of our traits. • A child receives half of his or her chromosomes from mom and the other half from dad, thereby inheriting both the copies of genes for each trait. • http://gslc.genetics.utah.edu/units/basics/tour/inheritance.swf
In the Beginning… • Most of us are familiar with the basics of human reproduction – the female egg (ovum) is fertilized by a male sperm… • The egg and sperm that you came from each contained half of your chromosomes. • The egg, from your mother, contained 23 chromosomes from one of her single cells (See meiosis) • But you’re not exactly half of your mom because the DNA from each set of her chromosomes got mixed up in the process of making her egg (recombination). zygote Illustration courtesy of http://www.novozymes.com/cgi-bin/bvisapi.dll/discover/discover_circle.jsp?cid=-10846&pid=11458&id=27495&lang=en http://anthro.palomar.edu/mendel/mendel_1.htm
How Many Combinations of Different Traits Can Parents Pass on to Their Children? The traits that you inherit from your parents depends upon the combination of chromosomes that you receive from each parent.
Oh, the possibilities! Illustrated below is just ONE possible combination of chromosomes that a child can inherit from your mother What mom might contribute: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 X http://gslc.genetics.utah.edu/units/basics/tour/inheritance.swf
But Wait! There’s More! You also inherit chromosomes from your father; here is ONE possibility What dad might contribute: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 X From each parent, there are 223 - or about 8,388,608 – possible combinations of chromosomes! That’s why we don’t look exactly like our brother or sister… http://gslc.genetics.utah.edu/units/basics/tour/inheritance.swf
Some of what you inherit from your mother are mutations… …Other mutations that you have at birth are due to random chance… …You may already sense that your mother is a mutant… …Does this make you one too?…
Genetic testing may help you find out some information about the mutations you carry, and where they come from • But…You may need to know more about your father’s genetics too. • Even then, it may be impossible to trace a particular mutation to its source – your mother or your father or random chance
OK, but should you get a genetic test anyway? If you get a genetic test, is this something to share with your mother? What would this mean?… • These are very difficult, and personal questions, that require careful consideration and reflection for most of us.
What We’ve Learned • We aregenetically related to our mother because we inherit one copy of her chromosomes. • The copy of our mom’s chromosomes that we inherit is not exactly “half of mom” because the genes get shuffled when her eggs are produced. • Genetic testing can tell us something about our relationship with our mother, but not everything.