Genetic 2.1: Recessive Autosomal

Question 1

What does a square, circle, diamond, two lines reference in a pedigree

Answer 1

Square = male
circle = female
diamond = unspecified sex/irrelevant
two lines = cosenguinity (same blood)

Question 2

Sex vs Gender in the pedigree

Answer 2

Sex = chromosomal
gender = identity

Gender takes priority with a note underneath

Question 3

What does a circle with a dot inside of it refer to?

Answer 3

This refers to a woman who is a carrier (often a heterozygote carrier of a recessive disease)

Question 4

What does a triangle refer to in a pedigree?

Answer 4

An abortion
If it has a line through it, it is a voluntary aborption

Question 5

Génotype vs Phénotype

Answer 5

Phenotype: appearance of the genotype

Genotype: the alleles and genes

Question 6

What is Maladie ou condition monogénique?

Answer 6

Maladie that is related SOLEY to one GENE. (Like cystic fibrosis is only CFTR gene)

Question 7

What is Hétérozygote composé?

Answer 7

deux allèles mutants différents à un locus donné

Question 8

What does it mean to be hémizygote?

Answer 8

l’homme n’a qu’un chromosome X, hémizygote
pour ses gènes situés sur le chromosome X

Question 9

What is Liaison génétique?

Answer 9

Exception à la loi de Mendel connected to the law of independent assortment:

Close genes can have a higher liklyness to segregate together

The further, the more independent

Co-ségrégation de 2 ou plusieurs traits (associés à
des gènes différents) ensemble à la méiose en
raison de leur proximité physique sur le même
chromosome

Question 10

What is Haplotype?

Answer 10

Its a liason genetique that always leads to these genes being transmitted together (from the same parent)

Groupe d’allèle de différents loci situés sur un même
chromosome et habituellement transmis ensemble
d’un même parent

Question 11

What is Co-dominance?

Answer 11

The phenotypical expression of two hétérozygotes alleles.

In flowers, white+ red will give pink

In humans, blood type for example AB etc

Question 12

Can a child have a disease if only one of the parents is a carrier?

Answer 12

Yes, ONLY IF DISEASE IS DOMINANT

No, if disease is recessive autosomal!!

For example, a carrier mother is sufficient to give bad X chromosome

Question 13

Given a Aa Aa couple, what is the probability to have an affected child?

Answer 13

Aa Aa can make:
AA, Aa, aA and aa

As such, 1/4 to have affected child

25% chances d’avoir un enfant sans la condition/maladie

50% risque d’avoir un enfant porteur

25% risque d’avoir un enfant atteint

Question 14

True or False,
In a family tree where one of the parents is affected and the child is affected represent a typical recessive autosomic disease.

Answer 14

FALSE

Usually, if parent is affected children will only be carriers!!

Question 15

Phénomène de nouvelle mutation (de novo) est extrêmement rare dans ce type de transmission

Answer 15

Transmission autosomique récessive

Question 16

Il n’y a pas de transmission d’une génération à l’autre.
* Les atteints sont en général dans la même fratrie
* Les hommes et les femmes sont atteints de façon égale

Answer 16

Transmission autosomique récessive

Question 17

You have a patient affected by an autosomique récessive disease. What can be said about her kids without knowing anything about the dad?

Answer 17

The kids will at least be carriers as the mother has both of her chromosomes affected

Question 18

How do you calculate the probabilty of a child being affected by two potetnially carrier parents?

Answer 18

P That Child is affected = P(mom is carrier) * 1/2 (probability of giving bad allele) * P (dad) * 1/2(dad)

Question 19

How do you calculate the probabilty of a child being carrier by two potetnially carrier parents?

Answer 19

P That Child is carrier= P(mom is carrier) * 1/2 (probability of giving bad allele) + P (dad) * 1/2(dad)