Loading

Module 1: Pedigrees

Apuntes
Study Reminders
Support
Text Version

Herencia de características recesivas ligado al x

Set your study reminders

We will email you at these times to remind you to study.
  • Monday

    -

    7am

    +

    Tuesday

    -

    7am

    +

    Wednesday

    -

    7am

    +

    Thursday

    -

    7am

    +

    Friday

    -

    7am

    +

    Saturday

    -

    7am

    +

    Sunday

    -

    7am

    +

XSIQ
*

Biology - Inheritance of X-linked recessive characteristics

Inheritance of X-linked recessive characteristics

* A father with the characteristic cannot pass the defective allele (on
an X chromosome) to his sons as he only passes on the Y chromosome to sons

* More males than females are likely to show the characteristic (a female
needs two X chromosomes with the defective allele [1] for her to show the
condition; a male only needs one)

* A carrier female (heterozygous [2] for that allele) [3] does not show
the characteristic but may pass the allele concerned to some of her sons
who will therefore show the characteristic. Sons get their X chromosome
from their mother.

If a characteristic or trait is passed down only from father to sons and
never to daughters, then the characteristic shows a Y-linked [4] pattern of
inheritance, for example, hairy ears in males. The inheritance pattern in a
family could differ from that expected because of random mutations. [5]
Sometimes individuals in a family are adopted and this can complicate
interpretation of pedigrees if the adoption is not known by the individual
concerned.

Practise working out inheritance patterns for a variety of pedigrees. Next
to each individual in the pedigree, write the symbols for the genotype. [6]
Work from the known genotype to the unknown.

Previous | Next

Links:
------
[1] http://alison.com/#
[2] http://alison.com/#
[3] http://alison.com/#
[4] http://alison.com/#
[5] http://alison.com/#
[6] http://alison.com/#