A SIX GENERATION FAMILY OF FJORD HORSES
Parentage control in horses in the Netherlands has been established in the early 1970s. After the testing became
routine, material that was tested (i.e. haemolysate/blood) was stored at -20°C. Down to the present day,
archiving of tested material has proven to be useful in new methods of parentage control. Parents who were
originally typed for 'classical' methods can be analyzed using new technologies, resulting in successful typing of
horses which died several years ago.
Horse breeding is usually based on large families in which family-history traces back for decades. Material
originating from early generations in horse families is interesting due to their potential to provide information and
knowledge on effects that are hidden in horse families constituting of one or two generations. In literature, no
publication was found in which parentage control was performed on horses in more than five generations; a
possibility to describe six generations is unique. The family presented here consists of six generations of mares
(all alive), whereas material from the oldest sire was stored since 1972. Taking it all in all, this resulted in a
horse family in which the animals could be typed for a series of markers.
In the early 1970s parentage control started in horses. At that time, tests for detection and analysis of hereditary
factors were based on markers that can be identified in blood - the blood group system and protein
polymorphism's. These tests were expanded throughout the years, resulting in higher quality and increasing
knowledge.
In recent years, new technologies have become available due to an increase of knowledge in (human) genetic
research based on DNA. Some of these research techniques have been applied to animal genetics as well, for e.g.
parentage control as it is performed today. Compared to 'classical' (i.e. blood group) analysis any material can
be used - blood, hair roots, semen, milk, etc.
A lot of experience has been gained internationally during the years of blood group typing and identification of
protein polymorphism. Parentage control based on techniques which use DNA as a source of genetic variation
are being used more and more.
Genetic research for DNA variation in horses will increase in the next years due to the use of new technologies.
For instance, disease prediction and detection, coat color, and sexing will become or are available to some
extent. High quality research requires families which provide information on diseases etc. Without large
families, research would not be possible.
Figure 1. Six generations of Fjord Horses (names and year of birth)
A six generation family of Fjord horses
Heleentje (born in 1963) is the oldest mare who is still alive in the family. After being mated to Westman (born
in 1948), Sunngard was born in 1972. In 1980, the mare Armgard was born. Her daughter Fjellgard was born in
1985. Via Jillgard (1989), the latest foal born in the maternal heredity is Rosegard (Figure 1).
DNA was isolated from all horses involved in the family. A number of DNA markers was tested using techniques
which are applied to parentage control as well. Analysis was based on 17 markers, which are encoded by three
letters and at least one number.
According to Mendelian inheritance, half of the characteristics present in an individual are inherited from the
sire, the other half from the dam. In the family presented here, markers proved to inherit according to Mendelian
laws. Half of the characteristics existing in Heleentje (generation one) should be present in the next generation. In
the second generation, eight out of 17 markers should display characteristics of Heleentje. Next generations
should display four (generation three) and two out of 17 (generation four) characteristics present in Heleentje.
Two markers disappear from the family after the first mating (HMS2 and VHL150). Twelve out of 17 markers
are still present after one generation. Two markers (ASB2 and VHL47) are present in the third, and one (HTG7)
is present in the fourth generaration (Table 1).
Table 1. Presence of DNA characteristics from Heleentje in further generations.
Characteristic marker Present in generation
HMS2, VHL150 1
AHT4, AHT5, HMS1, HMS3, HMS6, HMS7, HTG3,
HTG4, HTG6, HTG8, HTG10, VHL20 2
ASB2, VHL47 3
HTG7 4
Large families are indispensable in (international) research. Families that are currently available to projects (e.g.
Horse Genome Project) are mostly based on one sire with many offspring. 'Wide' families like these are certainly
useful, whereas multi-generation families provide insight in additional fields of interest like.
Post Scriptum
Data were published at the 'Plant & Animal Genome V' conference, 12-16 January, 1997, San Diego, CA, USA
(Poster 322).
W.A. van Haeringen.
Dr. van Haeringen Laboratorium b.v., P.O. box 408, Wageningen, The Netherlands
MAIL : VHL@BEDRIJF.DIVA.NL
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