Lecture 4 Flashcards
What happens if there are abnormalities on the other 22 pairs of chromosomes?
Greater differences in phenotype, greater chance of miscarriage, tendency to be fatal
What happens if there are abnormalities on the sex chromosomes?
Less likelihood of fatality and are more common. May cause developmental difficulties and inheritance is complex. More resilient when it comes to abnormalities of sex chromosomes.
What can cause a baby boy to become more feminine?
As the woman gets more and more pregnant, the body builds a natural resistance to testosterone.
Which parent determines the gender of the offspring?
Fathers, as there is a 50% chance of a Y sperm or an X sperm.
What chromosome has the most information?
X
What is one sex-linked trait that the X chromosome codes for and what happens with it?
Colourblindness. Men are more likely to have it since they only have one X chromosome-women need 2 X chromosomes to get it.
What happens when the father has the trait for colour blindness? (X-linked recessive trait)
All of the daughters will become carriers, sons will not
What happens when the mother is a carrier for colour blindness? (X-linked recessive trait)
Son has a 50% chance of being colour blind, and daughter has a 50% chance of becoming a carrier.
What is Rhett Syndrome?
A dominant X-chromosome disease that affects vitamin D absorption.
What happens with an x-linked dominant trait if the father versus the mother has it?
Father-All daughters will have trait, no son will
Mother-All children have 50% chance of trait
What is haemophilia?
A recessive x-linked condition where blood is more runny and does not clot when you cut yourself
What is anothe recessive x-chromosome condition?
Early baldness
What are genetic mutations?
When a new allele shows up out of nowhere without family history. Can be adaptive or maladaptive.
How often does the Albinism mutation come up?
1/20 000 babies.
What is Albinism?
Lack of skin pigmentation, vision problems, and sensitivity to light (can also occur in non-humans)
Why can’t mutations be defined to race?
Because no phenotype is exclusive to one race. We cannot be so distinct in our categorization of humans because we are all so diverse and unique.
How is Down Syndrome unique?
It is not an affected chromosome, but the result of an extra one on chromosome 21
What is down syndrome?
Disease with no family history, gives person a slightly shorter lifespan, intellectual challenges (varies among patients), heart disease/hole in the heart, and distinct facial features.
What is Trisomy 18?
Edwards Syndrome. Fatal after birth, due to apnea (inability to breathe
What is Triploidy?
When fetus has 3 sets of chromosomes (69 in all), fetus cannot survive, caused by two sperms or double head sperm entering the egg.
What can premarital testing and genetic testing do?
Show you family history and risk of passing on genetic diseases to offspring.
What can IVF do?
Filter out affected genes, help create a “normal” child.
